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What every POD HD 500 owner *REALLY* needs to know!
by perapera on 2013-01-02 16:24:30

Hi guys, sorry, no kidding here:

I really think these are important things not stated (or in some cases not clearly stated) in the manual, that you need to know to start seriously programming your POD HD

I ran some serious tests on my Pod HD 500 and here is what I found out,

I'll try to be as synthetic (but complete and clear) as possible, but this is going to be a long reading so sit down and take your time or just go surfing somewhere else

§ § §

1) the "famous" [input-1: guitar / input-2: variax] setting gives you different levels of signal depending on the position of the first *mono* effect block you use (amplifiers included), in particular you LOSE 6dB in the "pre" path in comparison to the path A/B or post path

(note that this is not the same as saying that you gain 6dB with input-2 to "same", read on).

[ if you don't know what I'm talking about just go and read this thread: What every HD500 owner needs to know!

http://line6.com/support/thread/74045?start=0&tstart=0

then come back here to hear a different opinion on the matter]

first of all, try it out:

- connect a guitar to the guitar input and the Left output to a full-range linear amp (or use your headphones)

- recall a "new tone" default blank patch

- set input-1 to Guitar and input-2 to Variax

- set mixer channel A fader to unity (0.0dB) and pan to center

- set mixer channel B fader to mute

- setup a noise gate* with the threshold set to 0% in "pre" position

(with this setting this IS a unity gain mono fx block)

- play thru it

- now if you bypass it, you'll hear that it  looses 6dB of level when it's active (I initially thought this was noise gate's fault, but it's NOT)

- now re-activate the noise gate and move it in A or "post" path

- now if you try to bypass it you'll hear that it does NOT loose any dB

- try moving the block back and forth ** between pre and A or post paths and you'll hear more level in path A or post than in pre

[please note that this was edited some minutes after posting for small but significant typo's]

this was already found out at least by hurghanico here: http://line6.com/support/message/403287#403287

but it's so important that needs a dedicated and more detailed thread.

[* you can repeat the experiment with other mono effects instead of a noise gate but keep in mind that, if you want to clearly hear a level difference, you need a mono unity gain (www.music-dictionary.org/unity_gain) effect, for example:

- a tube comp with thresh 100% & level 2% settings will work just  as the noise gate above

- an fx loop block with a mono cable connected between send and return will work just the same (but also read point 2 below)

- do it with an amp with medium-low gain and, moving it between pre and A or post paths, you'll hear a significant difference in gain/ovedrive/distortion here, not only level difference

** Notice that I found an intermittent bug here that could change the result of the test: see point 3) below]

OK now that you heard it, let's see it in detail;

these are the REAL schemes of the pod and fx blocks routing, yes it's done by hand and I love it ;-)

<a target=new href=http://dl.dropbox.com/u/8875989/Pod_HD_forums/pod_routing_%26_fx_blocks_graphs.png" class="jive-image" src="http://dl.dropbox.com/u/8875989/Pod_HD_forums/pod_routing_%26_fx_blocks_graphs.png"/>

As you can see the pre path is a "dual-path"

while A, B and post are all stereo paths;

at the splitting point, where the path A and B are born,

the signal coming from input-1 is splittted to the Left and Right channels of the path A

and the signal coming from input-2 is splittted to the Left and Right channels of the path B;

furthermore all fx blocks have TWO inputs and two outputs and the mono blocks do attenuate by 6dB and sum their inputs, then process the result and then split their mono output to both outputs of the block;

for those who don't know, notice that:

- summing two identical signals or doubling a signal, gives you the same signal with 6dB more

- "splitting" means duplicating one mono signal to two "routes", practically doubling it;

[and two side-notes:

- the "stereo dry & mono wet" effects are for example the pitch effects and the "dry" type delays, I'm not considering this type of effects in this post, but they work as expected from the scheme you see above;

- the mixer control named as "pan" is actually a "balance" control because if you move it to one side (e.g.: left) it acts on the stereo or dual mono signal by doing NOTHING on that side (left) and ATTENUATING the opposite side (right)]

So, if you only activate input-1, in the pre path, the first mono effect is attenuating the input 1 and 2 and summing them, but, since input-2 is actually silence, you loose 6dB;

in A and post paths the effects are receiving a doubled signal on L/R so for mono blocks attenuating and summing gives them the right mono signal level to process

so using "same" or "guitar" for input-2 does not mean to gain anything, but having a constant doubled signal wich is compensated by a 6dB attenuation in each mono summing it encounters in his flow

please note that I am NOT saying that using only input-1 is wrong, you just need to know that this can give you different gain results depending on the position of the first mono effect

with only input-1 active and the same parameters values, this:

<a target=new href=http://dl.dropbox.com/u/8875989/Pod_HD_forums/rout-1.png" class="jive-image" src="http://dl.dropbox.com/u/8875989/Pod_HD_forums/rout-1.png"/>

is giving you more distortion than that:

<a target=new href=http://dl.dropbox.com/u/8875989/Pod_HD_forums/rout-2.png" class="jive-image" src="http://dl.dropbox.com/u/8875989/Pod_HD_forums/rout-2.png"/>

and this is something that can not be ignored

...don't know how to be more clear than that

§ § §

2) the fx loop block is LOOSING 5dB on the send with the switch in the "stomp" position.

What I wrote untill here were just implications of how the routing of a complex multifx (like the pod hd is) can work; but now we go to something couter-intuitive and *guiltily* not stated anywhere in the manuals.

if you connect anything gain related (compression, distortion, preamps, envelope followers) into the fx loop you're getting the *wrong* result

this includes the very popular four-cable-method (http://line6.com/support/docs/DOC-2504)

Now I'm going to explain this and give a SOLUTION to the problem, let's see the details:

I have to say thanks to this post from anglepod (to whom I rashly replied that he was wrong and I'm gonna ask him his forgiveness for that): http://line6.com/support/message/393494#393494

and that I totally agree with the original post by jimsreynolds in this thread:

http://line6.com/support/message/397759#397759

but here I'm giving a different and easier solution I think

Anyway, what I measured is that, with the stomp/line switch on "stomp" and input pad on "normal", the guitar signal is attenuated by 5dB (approximated with no decimals) along his route from the input, thru no fx and then to the send jack, and is quite-compensated by gaining back 4dB at the return;

[this additional 1 dB difference (again approximated with no decimals) from -5 to +4 is even more inexplicable and could be only on my POD HD 500 unit, so you'll need to test your own]

furthermore, switching the stomp/line switch to "line" is (correctly) giving 12dB to the send AND compensating by attenuating the return by the same amount, but is "suffering" from the same -5/+4 attenuation/compensation, so you get +7dB at the send (+12 -5) and -8dB at the return (-12 +4) as a result;

I guess the reason for this attenuation/compensation is to put the unity gain at approximately half-way between a stomp and a line reference level, but this choice is wrong (or at least badly implemented and guiltily not documented):

common sense: when I connect my guitar directly to any guitar input (stomp-box or preamp) I have a "stomp" signal level, so:

- the stomp position of the switch should definitely be at unity (=same level as the guitar itself)

- consequently the "line" position should be +12dB on the send and -12dB on the return

- then we should (like anglepod noted) have the ability to give or take dB's on the send as well as on the return via some software trims

the SOLUTION to the problem is:

- set the fx loop switch to line

- set the send to -7 dB and the return to +8dB (could be e.g. -6 / +6 on different machines)

now you have a unity send and a unity return AND you can boost or attenuate both if you need it!

[

EDIT:

there are other solutions to this problem

see my post on the 9th of january

]

Then combining my 1) and 2) points:

if you connect a cable to just one of the fx return jacks (this works also with the Right return, not only the L/mono) the fx loop block acts exacltly like a mono fx block (see diagram above), so it attenuates and sums its inputs and then sends the result to the send jack (to both pins of the TRS jack to be precise), and then splits the return to both outputs of the block

this means that if you are using the [input-1: guitar / input-2: variax] setting and you put an fx loop in default mode into the "pre" path with for example your amp's preamp into it, you are loosing 11 (or 12) dB of gain!!

§ § §

3) I'm not spending time on this point because I've still to test it more but I'm pretty shure I found an intermittent bug on the action of moving an effect on the signal chain that complicates the investigation on all the things you read above (but doesn't deny them)

if you try to replicate the steps at the beginning of my point 1) above, if the bug presents itself (and it's not always), when you move an effect from the "pre" path  to path A it works correctly giving you 6dB more, but when you move it back to "pre" it doesn't go back to minus 6dB; if you save the patch and then move to another patch and come back using the pod pedalboard and *not* with the edit software, you can start over untill you move the effect again forth and back

Of course I'll submit this as a support ticket as soon as possible

4) OK, after all this reading, I'm asking something more to you;

please, since it took me days of work ("fortunately" I was ill at home in these holidays) to test, re-test and write all of this in english (which is not my mother language), you owe me this:

- re-read it (I'm not kidding)

- ask me any question you have (but don't expect me to be ill at home to much :-) )

- do all or some of the same kind of tests and then confirm, correct or deny my results

OR just shut-up, please ;-)

I hope to have been helpful to you... all that work was helpful for me!

thanks for reading and a happy new year!

bye

Lore



Re: What every POD HD 500 owner *REALLY* needs to know!
by snhirsch on 2013-01-02 17:54:40

Very nice work.  If you are correct in your analysis, this is the type of detail that really should be present in the advanced users guide.  Two minor points: 

1. No problem with hand-drawn figures, but it's difficult  to read the legends even after working on the png with a graphics program. 

2. Do you possibly have the "mono fx block" and "stereo fx block" legends switched?  Looks to me like that's the case, but perhaps I'm misunderstanding something.



Re: What every POD HD 500 owner *REALLY* needs to know!
by perapera on 2013-01-02 18:27:32

thanks snhirsch

1. if you click on the image it enlarges

2. you're completely right, I inverted the labels!

I corrected the image, but at this moment the line 6 server is not showing it, I'll retry later

thanks again

Lore



Re: What every POD HD 500 owner *REALLY* needs to know!
by CairnsFella on 2013-01-02 22:56:05

Thanks for this info and hard work. I am alread a 're-convert' to the guitar/same input approach, but I look forward to getting home and running through your examples nonetheless.

Thanks again (and I can read your writing ... but then my writing is worse



Re: What every POD HD 500 owner *REALLY* needs to know!
by dbagchee on 2013-01-02 23:23:27

This is great information. Thanks for taking the time to pick this apart. I just recently tried switching to variax on the 2nd input based on the other thread and definitely noticed a significant difference in the gain response from amps I had been using. I just assumed that this was how they were supposed to sound but now I will have to go back and look at my FX chains and I bet I'll see that I was getting the 6db drop (I almost always have the noise gate first, always on and in the "pre" path). I think this point you made is really important for people to note:

please note that I am NOT saying that using only input-1 is wrong, you just need to know that this can give you different gain results depending on the position of the first mono effect

This is just more information we need when we design our patches. I really hope Line 6 is paying attention to these discussions. Like others have said, the pedal should have "smart" defaults that setup the signal path correctly for the most common usage (80/20 rule). If I'm just using a mono chain I shouldn't have to be getting into all these deep parameters or understand the effects of improper gain staging.



Re: What every POD HD 500 owner *REALLY* needs to know!
by jimsreynolds on 2013-01-03 03:02:08

Still chewing through all of this but wanted to make one point regarding the FX Block.

Yes, you can turn the Loop Level switch to 'line' (with corrections to the send and return levels) as a way of boosting the FX send output.  The problem here is that you also raise the noise floor.  I tried this approach early on when I was trying to get my 4CM in order and the level of hiss that it introduced was significant.   The hiss level is not affected by the send/return levels on the loop and is constant.  This is why I rejected the approach ... which I agree, in principle should have been a great solution.

Another forum member, Gortur gave it a try on the thread here and found the same result -->http://line6.com/support/message/340532#340532">http://line6.com/support/message/340532#340532">http://line6.com/support/message/340532#340532



Re: What every POD HD 500 owner *REALLY* needs to know!
by hurghanico on 2013-01-03 05:51:43

Good job parapera


finally it was time for someone to open his eyes and trying to really understand how things are ..
in several past threads I tried too to explain how routings of the signal really work in relation to the input settings and the position of the blocks ..


now it's your turn ..


keep it up, and good luck


Hurghanico



Re: What every POD HD 500 owner *REALLY* needs to know!
by phil_m on 2013-01-03 06:34:15

This makes sense to me, and I appreciate all the work you put into it. I also like your wiring diagrams! The only thing that gives me slight pause is that the idea that the input signal is attenuated before being input into a mono effect actually contradicts what's actually in the Advanced Guide. On 6.2 it says this:

Note that when utilizing both Inputs 1 & 2 (or when using “SAME” for either of these Input options) the two Input signals are combined to allow them to be fed into any Amp or mono FX Model within the Pre position, which can result in a hot signal level. Reduce your instruments’ volume as needed to avoid overloading your Pre-positioned Models.

In this and in other places, the Advanced Guide seems to say that using only one input is the way to preserve a true mono input signal. So either you're right and the Advanced Guide is wrong, or there's some other sort of signal processing going on.



Re: What every POD HD 500 owner *REALLY* needs to know!
by perapera on 2013-01-03 07:10:56

hi jimsreynolds, what you say about noise could be true, but strange

my ipothesys in theory is that it's not the "line" position that amplifies but the "stomp" one that pads:

probably there are two 12dB fixed gain amplifiers at the send and return and the stomp/switch line is "moving" a 12dB pad from the send to the return; and this means same signal-to-noise ratio

my new tests confirm it:

please dounload and unzip this (1MB):

http://dl.dropbox.com/u/8875989/Pod_HD_forums/fx_loop_noise_test_perapera.zip

I recorded the noise of a unity gain patch vs the noise of the same patch with an fx loop with these settings:

switch to line, send -6dB, return +6dB, mix 100% and a mono cable patched between send and return

[tech note: I used the -6,+6 values instead of the -7,+8 I suggested in my original post because I still have to find out where that dB difference comes from and because it's easier to read, but if you do the same test with the default 0,0 you can compare stomp vs line just in the same way]

then I boosted everything by 40dB to make it easily audible:

NOISE 01 unity  vs fx loop line (-6,+6).wav

you can clearly hear (it's better to use headphones) more noise with the loop active, and this is perfectly normal since the fx loop is converting the signal D/A and A/D (digital to analog & analog to digital).

Now in the next file there is the noise of the same patch with an fx loop with the same settings followed by the noise of the same situation but with the switch to stomp

(again boosted by 40dB to make it audible)

NOISE 02 fx loop line vs stomp (-6,+6).wav

it's really hard to hear any discontinuity!

Just to be shure I retried the same experiment with a turbo rat pedal active in the loop instead of a simple cable

so in the next file there is the noise of the same patch with an fx loop with the same settings followed by the noise of the same situation but with the switch to stomp

(again boosted by 40dB, this time not to make it audible but for consistency)

NOISE 03 rat line vs stomp (-6,+6).wav

it's A LOT noisier (R'N'R to the Rat !! \m/ ) but in the line position it's actually less noisy !

Pay attention to this please: the whole point here is stop loosing 6dB of gain with the fx loop, and more gain means more noise!

if you compare (I did it) this: [fx loop on "line" with 0dB on send and return], it's a bit less noisy than that: [fx loop on "line" with -6/+6dB], but the reason for this is that it's giving you more level at the send (actually the right level) and attenuating at the return and this obviously gets more noise from the A/D converter

and anyway this should (should... read below) be the same as connecting the guitar to the effect/preamp you are using in the loop:

in other words, imagine a classic guitar > overdriven pre-amp only setup: if you then put a 6dB pad between your guitar and your preamp and a 6dB boost after the preamp you are going to get LESS noise AND LESS overdrive than bypassing the pad and the boost!, this intuitive

I did some other tests and the real point is that the pod itself is introducing more noise than the fx loop (in stomp or line position):

pod vs pod with fx loop 2/3db noise difference

pod vs true bypass 4/5dB noise difference

anyway I can live with that

thanks again

bye

Lore

p.s.

my girlfriend is gonna kill me for all this time spent testing and on-line, f**k! ;-)



Re: What every POD HD 500 owner *REALLY* needs to know!
by perapera on 2013-01-03 07:12:05

thanks Hurghanico!



Re: What every POD HD 500 owner *REALLY* needs to know!
by perapera on 2013-01-03 07:44:13

thanks phil_m

well, first of all many people here on the forums think that the whole forum itself would be WAY smaller if that guide was written correctly and thoroughly, so yes I will contradict it with confidence if I have to

BUT since:

- 99% factory presets and the "new tone" blank patch from the factory are setup with both inputs active

- the guide could be just conservative to avoid any nasty digital distortion,

for example if you set up an eq with a lot of gain (but NOT saturating) using just one input and then switch the second input to "same" you could get that distortion;

but the point is that anyone can hear by himself what I state at point 1) using my (and Hurghanico) test

- the most visualized thread on this forum entitled "What every HD500 owner needs to know!" basically says "do not do what the default settings and the guide tell you to do" that's why it had all that succes, if in the guide was written to use just one input, that thread would have ended receiving just one reply: "hey man, this is what the guide says at pages [6.2] and [...],  just RTFM !" ;-)

...I would say that the guide is so vague that it's not contradicting my statements in any way

AND I will raise the bet, justo to have fun, here is my challenge:

if within one month any line6 technician or expert user or anyone DOES NOT DENY my statements with technical proof and test,

my signal flow graphs are going to be put in the f***ing manual hand-written and with my autograph (thanks I don't want money for that)

sorry I slept too little this night ;-)

but I'm not joking :-|

bye

Lorenzo



Re: What every POD HD 500 owner *REALLY* needs to know!
by Akeron on 2013-01-03 08:15:02

Two years of arguing, pages and pages of obscure technical explanations and the solution is... use the default settings?



Re: What every POD HD 500 owner *REALLY* needs to know!
by TexLefty65 on 2013-01-03 09:02:49

phil_m wrote:

This makes sense to me, and I appreciate all the work you put into it. I also like your wiring diagrams! The only thing that gives me slight pause is that the idea that the input signal is attenuated before being input into a mono effect actually contradicts what's actually in the Advanced Guide. On 6.2 it says this:

Note that when utilizing both Inputs 1 & 2 (or when using “SAME” for either of these Input options) the two Input signals are combined to allow them to be fed into any Amp or mono FX Model within the Pre position, which can result in a hot signal level. Reduce your instruments’ volume as needed to avoid overloading your Pre-positioned Models.

In this and in other places, the Advanced Guide seems to say that using only one input is the way to preserve a true mono input signal. So either you're right and the Advanced Guide is wrong, or there's some other sort of signal processing going on.

Hi Phil,

Interesting discussion here. I don't see that Advanced Guide satement to be "incorrect" though. I think we're just getting beyond that concept into a deeper understanding and different ways to refine the signal chain here. I do recall there being a prevalent problem early on with POD HDs where guys with hot pickups were complaining that they were getting input clipping. I think a lot of that problem was a result of them using the default input routing (where both inputs received the Guitar signal) and then placing a mono amp/effect in the Pre section. So the Guide's statement does serve as a good caution for people running into that problem. I didn't read that statement to be a hard rule to "never use both inputs" since obviously you need to do that (when there is no mono block in the Pre section) to feed your guitar to both paths. I bet that if Line 6 instead made the default that Guitar was only set for Input 1, then a LOT of guys would not figure out how to get their guitar routed to both paths for a lot of presets. So I can see where they probably had to set this to be the default (as well as to have Variax and Line In active by default - so in most cases, most things "just work" when you start using the POD!)



Re: What every POD HD 500 owner *REALLY* needs to know!
by perapera on 2013-01-03 09:17:32

in reply to:

In this and in other places, the Advanced Guide seems to say that using only one input is the way to preserve a true mono input signal.

notice that this setup:

guitar input (no pad) > only input-1 active > no fx > mixer channel-A at unity and pan centered, channel-B muted > mono output

is at unity (but it's not strictly mono, it's actually mono to dual mono, then re-summed to mono at the output jack)

BUT if you insert a mono effect in the pre-path it looses 6 dB

while this other setup:

guitar input (no pad) > both inputs active > no fx > mixer channel-A at unity and pan centered, channel-B muted > mono output

is at unity (and again it's not strictly mono)

AND if you insert a mono (or stereo) effect anywhere including the pre-path it stays at unity

this is what I mean with tech proof



Re: What every POD HD 500 owner *REALLY* needs to know!
by hurghanico on 2013-01-03 09:21:02

phil_m ha scritto:

This makes sense to me, and I appreciate all the work you put into it. I also like your wiring diagrams! The only thing that gives me slight pause is that the idea that the input signal is attenuated before being input into a mono effect actually contradicts what's actually in the Advanced Guide. On 6.2 it says this:

Note that when utilizing both Inputs 1 & 2 (or when using “SAME” for either of these Input options) the two Input signals are combined to allow them to be fed into any Amp or mono FX Model within the Pre position, which can result in a hot signal level. Reduce your instruments’ volume as needed to avoid overloading your Pre-positioned Models.

In this and in other places, the Advanced Guide seems to say that using only one input is the way to preserve a true mono input signal. So either you're right and the Advanced Guide is wrong, or there's some other sort of signal processing going on.

actually the misunderstanding started exactly from what is written in parentheses (which I think is wrong and probably an oversight) in the phrase of the manual that you have reported here ..
taken away what is written in brackets, the rest of the sentence makes sense, since you can send simultaneously 2 different signals from 2 different instruments to a single mono effect or amp ..
therefore the 2 signals, even if halved, when combined together may give a too high signal level to the individual mono-fx/amp input..


and in fact over there is written "instruments", in the plural



Re: What every POD HD 500 owner *REALLY* needs to know!
by perapera on 2013-01-03 09:43:37

Akeron wrote:

Two years of arguing, pages and pages of obscure technical explanations and the solution is... use the default settings?

;-)

but ...beyond jokes:

the matter here is more accurately like:

"if you want the first effect you use to receive the correct level independently from his position in the signal chain, then set both inputs to the same source you are using (e.g. guitar/guitar);

if this doesn't work for you because you have hot pickups try one or more of the following:

- set the guitar input switch to pad (-6dB)

- lower the pickups (increase the distance from pickups to strings)

- try to disable input-2 assigning it to an unused input (e.g.: guitar/variax), but pay attention because this third point only works if you put your first effect in the pre-path"

this is obviously not like saying: "use the default settings"



Re: What every POD HD 500 owner *REALLY* needs to know!
by perapera on 2013-01-03 09:56:16

hi guys no more illness here so I'm going out with my girlfriend

please don't forget to like my original post

and support my challenge here: http://line6.com/support/message/405234#405234

peace

Lore



Re: What every POD HD 500 owner *REALLY* needs to know!
by hollis1003 on 2013-01-03 10:36:06

I think what most people on this forum want is an accurate representation of what happens when you plug in a guitar to real pedals and an amp. 

IMHO the best way to do that is use input 1=guitar and input 2=same. 

I wish someone would compile the long list of unanswered questions, even if we think we know the true answer, and let Line 6 respond.  Of course it won't happen, but I can dream.



Re: What every POD HD 500 owner *REALLY* needs to know!
by perapera on 2013-01-04 00:39:48

I think that to do  what people ask when they say there should be a "simple routing default"

you just have to use the default "new tone" patch (maybe with just guitat/same as inputs instead of everything/same to reduce hiss)

and just put effects either before the amp or after the mixer, simply ignoring mixer and paths A/B if they don't need them

this gives you the classic [guitar > pedal > amp > stereo multieffect] configuration without any routing hassle

the default patch in fact IS a "simple routing default"

Lore



Re: What every POD HD 500 owner *REALLY* needs to know!
by Akeron on 2013-01-04 03:03:00

perapera wrote:

but ...beyond jokes:

I wasn't joking The fact that periodically somebody gives a different interpretation on the same subject is crazy! I guess that was the Mayans best kept secret. Thank you anyway, what you've said made sense in a way, dear homonymous We will never ever know who is really right though...

PS: Oh no, I prefer the "wrong" settings,. What I'm going to do now...



Re: What every POD HD 500 owner *REALLY* needs to know!
by jimsreynolds on 2013-01-04 04:29:38

Hi

Again, still chewing through your findings (you have been a busy boy) but the fact remains that specifically with 4CM, you get a lot more hiss with the loop set to line.

The signal comes out of the Pod FX loop direct into the amp's guitar input.  The amp guitar input is designed for a signal around -10dBV.  The line output from the pod is at around +4dBu ... about four times the voltage.   For whatever reason, the ambient hiss level stays high and constant regardless of where you set the FX Loop Send Level.

You might replicate something similar by simply taking the Pod FX Send out to an amplifier and cranking up the amp level/gain to hear the net impact.  It ain't pretty and you cannot correct for it downstream in the hookup.

I did not go into deep investigations but I remember that, when I set a patch cable linking FX Send and Return and monitored hiss at the 1/4" output, the level of hiss was not increased when I switched from Stomp to Line.  I guess then that the FX Return compensates for whatever boost or cut there is in the FX Send.  However,  in the 4CM scenario the result seems to be Hiss.  Obviously this is much more audible with the amp in a high gain configuration. 



Re: What every POD HD 500 owner *REALLY* needs to know!
by jimsreynolds on 2013-01-04 04:47:23

TexLefty65 wrote:

I bet that if Line 6 instead made the default that Guitar was only set for Input 1, then a LOT of guys would not figure out how to get their guitar routed to both paths for a lot of presets. So I can see where they probably had to set this to be the default (as well as to have Variax and Line In active by default - so in most cases, most things "just work" when you start using the POD!)

This!

Whether it is better or not to use both inputs, setting the second input to variax causes minor routing chaos downstream and this would leave most casual users in a real mess.

The point of all this is that the routing and levels within the HD are complex. There are different scenarios for different users based on their requirements, shaped by choice of inputs, effects, effect locations, panning, mono/stereo, mixer channels in use, outputs in use, input pads ... and probably other stuff too.  

It has taken several years of end-user fiddling to get close to the full set of scenarios (and the work here by perapera is a good contribution to that).  IMHO ... this forum is serving its purpose: a grass-roots method of flushing out all of the uses and issues with the POD and documenting them.  The primary documentation could probably do with some additional material covering these subjects but if that ain't coming then this will do.

Perapera, I have little expectation that Line 6 will take up your challenge.  It just don't work like that.   It would involve a collaboration between support staff, technical authors and design engineers in a way that doesn't usually happen as an ad-hoc exercise within a business unless there is a very strong imperative.  Happy to be proven wrong.



Re: What every POD HD 500 owner *REALLY* needs to know!
by Jeffsco on 2013-01-04 10:48:59

The links to the Dropbox details do not seem to be working. Any suggestions on how to access the flow diagrams?



Re: What every POD HD 500 owner *REALLY* needs to know!
by PDKTDK on 2013-01-04 11:03:16

Outstanding!

Hurghanico (and now you) have been getting a lot of my attention lately.

Does anyone know if this would apply to a L6 Link-ed DT amp?



Re: What every POD HD 500 owner *REALLY* needs to know!
by perapera on 2013-01-04 14:14:07

I wanted to get rid of the dropbox links for the images and uploaded them directly on the forum but the line6 server must have some problems

so now I re-uploaded the images on dropbox

thanks for the warning Jeffsco!



Re: What every POD HD 500 owner *REALLY* needs to know!
by spikey on 2013-01-04 22:05:05

hollis1003 wrote:

I think what most people on this forum want is an accurate representation of what happens when you plug in a guitar to real pedals and an amp. 

IMHO the best way to do that is use input 1=guitar and input 2=same. 

I wish someone would compile the long list of unanswered questions, even if we think we know the true answer, and let Line 6 respond.  Of course it won't happen, but I can dream.

What I wanted was somthing simple to use that sounded killer.... I think I got a little of the last part....



Re: What every POD HD 500 owner *REALLY* needs to know!
by perapera on 2013-01-09 09:51:34

Hi guys

Last night I found the time to test again the fx loop for the hiss topic that jimsreynolds pointed out (thanks jim!) :-)

...well, he is right !

I'm not going to report all the tests, just some conclusions:

first of all: keep in mind that, if you use the 4-cable method (http://line6.com/support/docs/DOC-2522) to connect to an external preamp you have to be very careful in your choice of settings on the pod or you can get more noise or less gain or even more gain than what should be.

the conclusions of my tests are:

1) the pod itself is adding some noise (e.g. gtr > pod > amp has more noise and hiss that the true-bypassed signal)

2) the 4 cable method adds even more noise because it passes thru the pod 2 times

3) as I said, the fx loop send with the switch on "stomp" does attenuate by -5dB and gives you A LOT LESS gain at your preamp, than if you connected the guitar directly to your preamp (and this is UNACCEPTABLE);

then the level is compensated at the return by a +4dB boost.

4) then comes the "solution" I offered in my original post:

if you use the fx loop with these settings:

switch on "line", send: -7 , return: +8 (these values could be precise only on my Pod HD 500 machine, but the order of magnitude is this)

you get the right gain and level (unity gain)

BUT you get more hiss than what it should be

(getting more gain gives more noise of course, but this is even more)

I tried the stomp and line positions of the fx loop switch, compensating in various ways to their boost/attenuation and the stomp has a little more hum while the line has clearly more hiss

5) I tried a similar solution to the one offered by Jim here http://line6.com/support/docs/DOC-2522 at point 4 of the "Patch Setup - Effects Only"section

[note that the studio eq gain pot is labeled in dB's but the values are wrong (I found that to have a real 6dB boost you need to see "8dB" on that pot)]

anyway I used these settings:

- fx loop switch on "stomp", send: 0dB and return: 0dB

- a tube comp (settings 100% , 17%) giving +5dB before the fx loop

- a fixed volume pedal (at 78%) attenuating by -4dB after the fx loop

I'll call this the "minus two fx-blocks solution", even if it's not an idea of mine, because it's easier to recall

that gave me the correct gain and level (unity gain) but with a lot less hiss than my "line, send: -7 , return: +8" or "line attenuated" solution

of course it's (at least) ridiculous to loose two fx blocks to compensate for a hardware design fault

(I don't think the -5dB send level loss is a fault in my specific unit because many people have found the same problem and because also the output jack switch on "amp" is loosing, oddly enough, -5dB with the master at full)

and of course, depending on your fx-chain into the pod you could:

- use the mixer as a boost OR cut and loose only one fx block

- use other effects (which must include a volume control) that you normally leave always on, as a boost and/or cut

- use an external analog clean boost and attenuation

- compensate with your anp gain and volume controls

but anyway you put it, each of these solutions end up as a workaround that the pod needs to let you do a simple thing

as of me, having to choose a workaround I'm going to stick to my "line attenuated" solution, keeping the hiss and having at my disposal two more fx blocks plus the ability to boost and cut the send and the return

[EDIT: in the end I actually chose this solution even if I loose an fx block (I use the switch on the stomp position and a tube comp with threshold 100 and level 17), BUT I decided NOT to compensate for the +4dB given by the return circuit or I would have to loose another block; so in the end it's a "minus ONE fx-blocks solution"]

oh my god, how much did I write?!?

bye

Lore



Re: What every POD HD 500 owner *REALLY* needs to know!
by drewfx on 2013-01-10 15:06:40

I ran into all this when I had an HD500 for effects only; I couldn't for the life of me get a clean signal-path. At the time it was more important to me to use the HD500 for effects, so I sent it back to the shop.

Line 6 need to fix this really, although I don't know if they can?



Re: What every POD HD 500 owner *REALLY* needs to know!
by MartinDorr on 2013-01-11 12:18:37

I can confirm your Stuido EQ finding that the dialed in dB gain is usually off by a fair amount (up to 2dB like you found) between -18dB and 0dB as well as between 0dB and +18dB. It really Also make sure you are not trying to get more than  -12dB output from the Stuido EQ. If you do the Studio EQ will add compression, soft clipping and finally hard clipping (distortion) at the point when you exceed -3dB output. You may also want to stay below -12dB on the input side if you are looking for no gain pass through as it will reduce your level depending on how high above -12dB you come in. In summary, there are 2 effects at work in the Studio EQ: Its dialed in dB value is usually not what it usually produces and if you come in or go out above -12dB it will compress and finaly distort depending on how much higher than -12dB  you are coming out. Once you get into the compression range on the output the gain dials of the Studio EQ are even further off (output is always lower than what you think you dialed in).



Re: What every POD HD 500 owner *REALLY* needs to know!
by perapera on 2013-01-16 05:48:20

thanks MartinDorr

I can in part confirm what you said also in the second part of your post (eq limiting and saturation), but I think it needs to be clarified for other people reading this thread, who do not use professional means of testing

[for nerdy tech notes read the second part of this post]

1- please remember that, as the "model guide" says, this fx is an equalizer "Inspired by API® 550B. Featuring a constant Q and Soft Clipping output with level control" so the studio eq is not a digital "clinical" eq, it's an analog modeled analog eq which adds (odd) harmonics and soft clipping as a desired effect

2- in addition to this, we both found that the output level knob has a different labeled value from the actual signal gain obtained (a read value of +/-8 equals a real +/-6dB) and this has no reason to be (the analog API 550b doesn't even have an output gain!)

3- for these reasons I think the studio eq simply is not the ideal one if what you need is just a clean boost/cut;

the mixer's faders and the volume pedal are the only completely transparent digital volume controls, but the volume pedal can only attenuate and the mixer cannot be moved around;

in my tests (with a guitar with a dimarzio superdistortion on the bridge position) the tube comp is cleaner than the studio eq even at unity (the tube comp unity is at 100% threshold and about 3% level )

Anyway the studio eq is essential for a stereo signal (not the case with the 4 cable method)

4- and finally the -12dB you are talking about (read the notes below to see if I'm correct), is a HOT signal, so we are going to get some clipping only on high level peaks which could be desiderable

(and the -3dB is not even reachable for a standard guitar signal)

peace,

Lore

                                                                                   §§§

P.S.: nerdy tech notes

If I understand correcly, when you talk abount "-12dB", you are talking about sending to the pod or measuring at the output of the pod, a signal of -12dBFS (digital Full Scale)

As you may know, a digital value measured in dBFS unfortunately does NOT have a standard analog counterpart!

And that's because the analog value depends on the actual specifications of your audio card (or signal generator or meter...)

so I think it makes a little sense to talk about digital levels if you are interfacing analog and digital devices

(or digital devices with analog signals and cables)

but anyway

supposing your interface has a +22dBu max out the -12dBFS corresponds to a +10dBu which equals to +8dBV; this means 18dB more than the reference level for normal guitar pedals (which is -10dBV)

I tested it and you're right: with a signal like that (10 to 12dBu), the studio eq, even at unity gain, starts to soft clip and adds harmonics (the tube comp does not, it needs 4dB more to add some harmonics)

BUT, again:

this is a HOT signal that a guitar can only reach on higher peaks

my advice (for anyone) is: test it with your guitar, use a patch with only the eq and the tube comp set-up for the same gain and listen with headphones toggling the two, then try it thru your amp and your full setup whith you actual routing and choose what you like more.



Re: What every POD HD 500 owner *REALLY* needs to know!
by MartinDorr on 2013-01-17 13:40:28

I like your response! Thanks for sharing your deeper insight into this topic. I think you are right on that one need to consider what outputs are in use before getting all worried about the levels and how the modeling gets affected. I stumbled over the Studio EQ behavior (actually the Mid Focus EQ does the same) when looking at USB output signal levels. What cought my attention was that although my DAW meter said I was at -6dBFS peak (quite a bit away from a digital cipping point) the Studio EQ added compression and a bit of distortion. Something I simply did not expect.

I also agree with you that Line 6 is probably just emulating what the real HW does at high levels in the -12dBFS to 0dBFS signal level range, essentially emulating the real behavior of analog equipment.

By the way, my JTV comes in at about -16dBFS using the digital interface. So it's not so far off from the hot -12dB. Also, if you use high gain amps it does not take a very high Drive setting to hit into the -12dB range with channel Volume at or above 50%. Maybe something to consider when you can't mesure and care to not get any unwanted distortion or compression.



Re: What every POD HD 500 owner *REALLY* needs to know!
by lindsayward on 2013-01-21 18:34:16

Hi!

I don't use the 4CM or the FX loop at all. I just want good clean sounds - I want good dirty sounds too, but I don't want unwanted dirt

I do use a Studio EQ as my standard 'clean boost' option, at the front of the chain. I just tried it with the Tube Comp on Threshold 100% and Level up enough to sound about the same output as the Studio EQ on +5dB, which was about 12% for me. I alternated between them but couldn't tell much difference if any, except that without a noise gate, volume turned up and not playing the guitar, the comp had a slightly dirtier fuzz than the eq... although I just tried it again and couldn't tell the difference.

I'm using a simple JTV (Variax) -> POD -> PA (mono XLR) setup, no FX loops or amps in the chain.

I want to know what I can simply get out of this whole discussion to make my clean patches as nice and clean as I can, and the overall sound as good as possible.

Any useful distillation would be most helpful thanks.



Re: What every POD HD 500 owner *REALLY* needs to know!
by Ed_Saxman on 2013-01-21 18:57:09

I want to know what I can simply get out of this whole discussion to make my clean patches as nice and clean as I can, and the overall sound as good as possible.

Any useful distillation would be most helpful thanks.

Put everything on path A, pan centered, with the mixer last in the chain. Mute Path B.

<a target=new href=http://i812.photobucket.com/albums/zz46/Ed_Saxman/Capturadepantalla2013-01-16alas145424_zpsd10819ec.png" class="jive-image" height="107" src="http://i812.photobucket.com/albums/zz46/Ed_Saxman/Capturadepantalla2013-01-16alas145424_zpsd10819ec.png" width="428"/>

This is what as a HD500 owner I *REALLY* needed to know from the beginning.



Re: What every POD HD 500 owner *REALLY* needs to know!
by spaceatl on 2013-01-21 18:58:42

<a target=new href=http://www.apptrav.com/popcorn-sutton.jpg" class="jive-image" src="http://www.apptrav.com/popcorn-sutton.jpg"/>



Re: What every POD HD 500 owner *REALLY* needs to know!
by Ed_Saxman on 2013-01-21 19:05:58

Marvin "Popcorn" Sutton!

He was a short, skinny fella, who always wore his hat—that was kind of his claim to fame, his hat that he always wore. And his bib overalls—he always wore bib overalls. Even when he came to federal court, he was wearing bib overalls. He was a friendly fellow, and of course every time you would talk to him, he would say, 'Ray, I’ve run my last run of moonshine, I'm not gonna do it anymore, I'm just getting too old to be doing this stuff.'



Re: What every POD HD 500 owner *REALLY* needs to know!
by perapera on 2013-01-22 03:17:14

sorry, I'm gonna have to quote myself:

"try it thru your amp and your full setup whith you actual routing and choose what you like more."

in other words: using the studio eq or the tube comp as a clean boost is not going to ruin your sound,

it's going to clip only the highest peaks, so if you use it at the beginning of the chain and with a passive guitar you could never hear anything "strange" (your peaks could be under their threshold of clipping)

my testing was with a dimarzio superdistortion, not the quietest and not the loudest pickup out there

I didn't notice any increment in background noise from the tube comp, but it could be

and, just to clarify, when I wrote "clean boost" I was speaking of a "transparent digital" boost to compensate for the badly designed fx loop;

this can only be achieved by the mixer's fader, but its position in the fx chain is quite fixed... so you need to chose something else

these are three clips from my test, looping the same notes to three routings (634KB):

http://dl.dropbox.com/u/8875989/Pod_HD_forums/tubecomp_vs_studioeq_test_perapera.zip

blank +5dB.wav

blank patch, boosted digitally in my daw

studio eq +5dB.wav

just the studio eq  (gain +7,4 which equals +5dB real)

tube comp +5dB.wav

just the tube comp (thr 100 - level 17)

(in case you are asking yourself... the clipping does NOT come from anything but the two fx blocks!)

even if the tube comp is a little less clipped I sincerely couldn't have chosen between the two, but...

...in my setup the tube comp works best, so I use it

i.e. if you try it with an amp (simulation or  real) after the blocks, the amp saturation could cover those clippings and make them more pleasant in two different ways: my amp prefers the tube comp

again "choose what you like more"...

or you could wear a bib overall and go moonshining ;-)



Re: What every POD HD 500 owner *REALLY* needs to know!
by perapera on 2013-01-22 03:20:04

and for the path-A only solution by Ed_Saxman:

yes this routing is a simple solution for a straight fx chain, it's like an HD400 with more fx blocks

also in that situation if everything stays on path A, the input-2 setting does not matter (same, guitar, variax, aux...) : you get anything you choose from Input-1 at the right signal level on path-A

anyway, what comes from my understanding of the signal routing in the PodHD is that even if you use a default "new tone" and just IGNORE paths A and B and the mixer you get the EXACT same result: an HD400 whith more blocks!

so why changing the default?!?

see also this post of mine which has pictures:

http://line6.com/support/message/405169#405169

P.S.

...still waiting for Line6 to officially confirm or deny of my routing graphs



Re: What every POD HD 500 owner *REALLY* needs to know!
by hurghanico on 2013-01-22 04:26:45

perapera ha scritto:

...still waiting for Line6 to officially confirm or deny of my routing graphs...

I do not think that Line6 will never give any confirmation or denial of this explanation of the facts ..


they prefer that people see the flexibility rather than all the details and the exact measurements, in the same way as they have not
more explained (compared to older modelers) which exact controls are actually provided by the objects that have been modeled, for example the presence or not of the presence and the mid controls in some amps ..


even though the models and the system very well take their cue from reality, the whole thing is given as a palette of colors with which to mess as you like to make your own creations, this also explains why some values ​​are expressed as a percentage and not in absolute value ..


and perhaps another reason could be that if they declared that every detail was 100% identical to the reality, someone might have to say that making comparisons and
measurements is not exactly so .. therefore remaining vague, they are saved from this occurrence ..


so I would say if this is the basic philosophy, all these details will never be revealed ..



Re: What every POD HD 500 owner *REALLY* needs to know!
by Akeron on 2013-01-22 04:28:35

perapera wrote:

P.S.

...still waiting for Line6 to officially confirm or deny of my routing graphs

http://memegenerator.net/Waiting-Skeleton">http://memegenerator.net/Waiting-Skeleton">http://memegenerator.net/Waiting-Skeleton



Re: What every POD HD 500 owner *REALLY* needs to know!
by perapera on 2013-01-22 04:47:02

I don't think so

I think the majority of guitar players who buy a Pod HD500 just do it for having more fx blocks than the HD400 at good price and not for the complex routing,

and they will never start to compare a vintage AC30 miked with a U87 with the pod (go figure an API to the studio Eq)

and Line6 do know it wery well

anyway I think they are overlooking the professionals and semi-professionals who like me just want to know what they are doing with their signal

and I think they want to keep the manual small by not explaining everything because they do not want to fear the average "wah>screamer>delay>amp" guitarist with lots of pages

and because they don't want to spend money on a REALLY advanced guide

that's all

p.s.

I wrote private messages to the Line6 guys here on the forum some minutes ago, let's see what happens,

I think that many "likes" to my original post would encourage them to make an official statement



Re: What every POD HD 500 owner *REALLY* needs to know!
by spaceatl on 2013-01-22 05:25:49

just trying to offer some "useful distillation"...



Re: What every POD HD 500 owner *REALLY* needs to know!
by hurghanico on 2013-01-22 05:59:13

perapera ha scritto:

...I wrote private messages to the Line6 guys here on the forum some minutes ago, let's see what happens,

I think that many "likes" to my original post would encourage them to make an official statement...

have you ever heard about NDA?

http://en.wikipedia.org/wiki/Non-disclosure_agreement

the Line6 guys are constrained by that agreement



Re: What every POD HD 500 owner *REALLY* needs to know!
by phil_m on 2013-01-22 06:14:31

I'd be surprised if they issue any sort of official statement. For one thing, I think I most users don't really care about the technical details as long as they can get the product to sound good. And really, why should they care? The Line 6 guys who are on the forums here are customer service people. The most they can do is pass info on to others in the company. Perhaps the Advanced Guide would be edited a little, but I don't see them totally revising it at this point. We're already over two years into the HD's life cycle, for one thing.



Re: What every POD HD 500 owner *REALLY* needs to know!
by perapera on 2013-01-22 06:49:19

guys please

we're not talking about revealing the god-existence formula

or saying that the whole POD HD line is a conspiracy against guitarists

they just have to say "yes this is how the internal routing of the pod works"

I repeat that my routing graphs do NOT contradict the manual in any way,

they just show more precisely (and more clearly, if you know how to read them) how a complex digital multifx works

(I learnt how to read signal flow graphs on the manual of my first lexicon mpx500 more than 10 years ago... it's price was more or less like the pod hd 500)

for example, if they published similar graphs into the first version of the manual, the whole input settings debate wouldn't have existed



Re: What every POD HD 500 owner *REALLY* needs to know!
by meambobbo on 2013-01-22 07:48:14

this is why i thought it would have been smart for line 6 to include some templates or use cases that could be switched back and forth on any patch that would go through the half dozen or so most popular use cases.

1) mono guitar - single amp - stereo/mono post effects (no dual paths, no mixer)

2) guitar + variax mixed - single amp - stereo/mono post effects (for mixing both mags and variax input into the same path...or switching between which is used on your variax) (input 1: guitar, input 2: variax, no dual paths, no mixer)

3) guitar + variax - independent paths (input 1: guitar, input 2: variax, default 4 blocks each in Channels A and B, not pre-split or post-mixer, default amp in channel B to none)

4) guitar + vocals - independent paths (same as above but input 2: mic)

5) guitar + aux - independent paths (same as above but input 2: aux)

6 play along - guitar + aux - independent paths - aux dry (same as above but all 8 effects blocks in Channel A)

7) mono guitar - dual amps (essentially what we have now with input 2: guitar/same)



Re: What every POD HD 500 owner *REALLY* needs to know!
by Ed_Saxman on 2013-01-22 07:53:23

Meambobbo Wrote:

this is why i thought it would have been smart for line 6 to include some templates or use cases that could be switched back and forth on any patch that would go through the half dozen or so most popular use cases.

1) mono guitar - single amp - stereo/mono post effects (no dual paths, no mixer)

2) guitar + variax mixed - single amp - stereo/mono post effects (for mixing both mags and variax input into the same path...or switching between which is used on your variax) (input 1: guitar, input 2: variax, no dual paths, no mixer)

3) guitar + variax - independent paths (input 1: guitar, input 2: variax, default 4 blocks each in Channels A and B, not pre-split or post-mixer, default amp in channel B to none)

4) guitar + vocals - independent paths (same as above but input 2: mic)

5) guitar + aux - independent paths (same as above but input 2: aux)

6 play along - guitar + aux - independent paths - aux dry (same as above but all 8 effects blocks in Channel A)

7) mono guitar - dual amps (essentially what we have now with input 2: guitar/same)

That would have been amazing!

Although we could still do that, with screenshots and all that stuff! Something that is easy to understand, and useful for everyone.

perapera wrote:

and for the path-A only solution by Ed_Saxman:

yes this routing is a simple solution for a straight fx chain, it's like an HD400 with more fx blocks

also in that situation if everything stays on path A, the input-2 setting does not matter (same, guitar, variax, aux...) : you get anything you choose from Input-1 at the right signal level on path-A

Yes, does not matter since Path A is a straight chain and Path B is muted, but you can also use the path B to have a unprocessed signal on input-2(Same) using this routing. Or a different instrument/mic on Path B. In this way you can record 2 mono channels (wet/dry) at the same time on your DAW (panning all the way L/R this time).

Since I never use dual amps/cabs, this is the way that makes more sense to me. And the easiest by far, if you want to make things works without complicated tech-talk, trial-and-error, more-tweaking-than-playing, or any weird  effects due to the dual inputs headache. (ty again, Meambobbo)

perapera wrote:

anyway, what comes from my understanding of the signal routing in the PodHD is that even if you use a default "new tone" and just IGNORE paths A and B and the mixer you get the EXACT same result: an HD400 whith more blocks!

so why changing the default?!?

see also this post of mine which has pictures:

http://line6.com/support/message/405169#405169

Becouse the default "new tone" is/was very confusing to most people, including myself. I´m afraid I prefer go single-arm-chain, wear bib overalls and go moonshining all night long, probably like most users. (And no, I don´t want a 300/400!)



Re: What every POD HD 500 owner *REALLY* needs to know!
by meambobbo on 2013-01-22 07:54:03

one things i wanted to mention about the tube comp.  it sounds transparent for most frequencies, but it actually is a low pass filter, with the cutoff frequency around 8kHZ.  Not really noticeable for most clean patches, but it's very obvious on bright, high gain patches.  usually you want a low pass anyway, so it certainly doesn't make it a dealbreaker - just something to be aware of.



Re: What every POD HD 500 owner *REALLY* needs to know!
by meambobbo on 2013-01-22 08:12:36

as far as i can tell on routing, everything Lore is saying is correct.  i don't know exactly about all the precise level adjustments (6db vs 5db, etc), but I would defer to his research.

Let's do a walkthrough example.  Let's say Guitar in is 100% volume.  Input 2 is Variax/null.  in the case of a mono effect in pre-split position, you get a halving of each input signal (100%/2 and 0%/2 = 50% and 0%).  Then they are summed (50% + 0% = 50%).  The processing occurs (let's assume level-neutral) than the output is duplicated and sent to both outputs.  So the output of the mono effect is two 50% signals.  When the left/top one hits the split, it is duplicated and we have two 50% signals hitting whatever is in Channel A.

Now let's assume there are no mono effects in pre-split position.  The 100% left/top signal from the Guitar Input is duplicated at the split and sent to Channel A.  So Channel A gets two 100% signals.  When it hits the first mono effect, they are divided in half (two 50% signals) and summed (back into a 100% signal). This signal is processed then duplicated to send to each output.  So each output is two 100% signals.

Test it for yourself - Lore is correct.

FWIW, I prefer Input 2: Variax, placing a Noise Gate and/or Distortion effect in pre-split position, and using dual amps (really the same amp but different cab/mics).  So I like the halved levels - I find I have more control over my distortion (I do use fairly hot pickups).  I also sometimes place a volume effect with a fixed setting of 60-80% to attenuate the signal early in my chain before it hits any level-dependent effects.  This is sometimes necessary to prevent EQ's from clipping (note that EQ's are stereo effects and aren't first attenuated like mono effects).  It's probably better to place a Noise Gate in front of them.  But I also use it to prevent a Distortion effect from giving ANY distortion whatsoever, so I can use it just as a filter.

I also have no clues about the FX loop mysteries.

Line 6 employees can relay questions to the engineers.  This is how we got an official answer to the harsh/fizzy/digital distortion thread - that the distortion was modeled crossover distortion.  It shouldn't be this hard to get an official answer on how the product works.



Re: What every POD HD 500 owner *REALLY* needs to know!
by perapera on 2013-01-22 09:45:18

meambobbo wrote:

Test it for yourself - Lore is correct.

thanks meambobbo

glad to have you on our side!

and the template idea is a good one, but without a clear explanation on the manual anything but the first one would have been confusing too,

and (just speculating here) probably when you created a patch with a template without pathsA/B and then decided to upgrade to a parallel path you would loose all parameters you created, unless Line6 did a very thorough programming job...

Ed_Saxman wrote:

Becouse the default "new tone" is/was very confusing to most people, including myself. I´m afraid I prefer go single-arm-chain, wear bib overalls and go moonshining all night long, probably like most users. (And no, I don´t want a 300/400!)

I totally agree Ed, the "new tone" is confusing, because it's not well explained in the manual

what I'm trying to say is that everything would be less complicated if they published two more pages, one with routing graphs and explanations and one with a list of steps that you needed to do to reach each "template" situation (like the meambobbo's), starting from the same "new tone"

and with these posts I'm trying to compensate for that lack of clarity in the manual

it should have been written:

"template 1 - mono guitar - single amp - stereo/mono post effects:

recall a new tone choose your amp and effects and ignore the two paths and mixer"

isn't this even simpler than path A only?

"template 2 - guitar + variax mixed - single amp - stereo/mono post effects

same as above but change input-1 to guitar and input-2 to variax"

and so on...

p.s.

of course the moonshinging thing is just a joke, but if you go up there please send me some bottles!!



Re: What every POD HD 500 owner *REALLY* needs to know!
by hurghanico on 2013-01-22 13:03:55

perapera ha scritto:

.....2) the fx loop block is LOOSING 5dB on the send with the switch in the "stomp" position.

What I wrote untill here were just implications of how the routing of a complex multifx (like the pod hd is) can work; but now we go to something couter-intuitive and *guiltily* not stated anywhere in the manuals.

if you connect anything gain related (compression, distortion, preamps, envelope followers) into the fx loop you're getting the *wrong* result

this includes the very popular four-cable-method (http://line6.com/support/docs/DOC-2504)......

-------------------------------------------------------------------------------------------------

.......if you connect a cable to just one of the fx return jacks (this works also with the Right return, not only the L/mono) the fx loop block acts exacltly like a mono fx block (see diagram above), so it attenuates and sums its inputs and then sends the result to the send jack (to both pins of the TRS jack to be precise), and then splits the return to both outputs of the block.....

First, I state that I have never used the fx loop and then what follows is only a hypothesis, fruit of reasoning and is not validated by concrete experiments ..

let us put aside the manual for a moment ..

if we look at our HD500, we can see that the outputs and inputs that can be used to give/get a (summed to) mono signal are clearly indicated ..

UNBALANCED.JPG                               BALANCED.JPG 


  FX LOOP.JPG

on the
FX SEND output the only indication that I read is TRS STEREO, so I thought: could be that this output is only and exclusively stereo? .. I know that it wouldn't make much sense if it was so, but if it was true, inserting a standard mono (TS) cable into an output like this, you would get only the left half of the signal, and in this case a way to recover the missing part might be to use a TRS-to-TS cable..

PS.

doing a little search on this site I noticed the the FX LOOP SEND output has undergone several changes in some firmwares..

it has been only mono, then it became only stereo, then it became stereo/mono, currently I don't know what it is really..


keep experimenting


A bit of history:

http://line6.com/support/message/331918


--------------------------------------------------------------------------------------
POD HD500 Flash Memory v1.40 RELEASE NOTES

Bug Fixes


  • FX Loop – In a mono configuration the FX loop does not sum left/right signal properly – FIXED

-------------------------------------------------------------------------------------

POD HD500 Flash Memory Version 1.31 RELEASE NOTES

What's new since v.1.22?

  • TRS-jack FX Loop Send is now sending a  true stereo signal, not summed mono. If you are using a mono cable, the Left audio path is sent. 


Re: What every POD HD 500 owner *REALLY* needs to know!
by perapera on 2013-01-24 01:23:32

I'm not aware of the history because I bought the POD HD already with 1.4 frimware

what I can tell you is that (with versions 2.02 and 2.10 at least) the fx loop when a single jack is connected to one of the RETURN jacks works like a mono fx block (despite what is written on the POD itself, this is valid for left or right return jacks)

the reason is that no TRS jack can be aware of what kind of jack is connected to it (TS or TRS) while a mono jack can have a switch inside it to "understand" if a jack is connected

as a mono block (see my graph above) it attenuates the 2 signals at its input by 6 dB and then sums them and sends this mono signal on BOTH tip and ring of the TRS,

then at the return it takes the signal from the return jack you decided to connect to and sends it to its outputs

so as any mono effect if you put it in the "pre" path and you select input-1: guitar / input-2: variax you loose 6 dB

BUT

the 5 dB loss I was talking about in my original post is ADDED to this and has nothing to do with mono summing



Re: What every POD HD 500 owner *REALLY* needs to know!
by perapera on 2013-01-24 02:17:33

this was my test:

guitar > guitar in > input-1 >

microphone > mic in > input-2 >

> fx loop block ("stomp" position) > send > TRS to 2 mono TS cable > a stereo track in my daw

- now, if I connect 2 dummy jacks to the two returns, the stereo track has guitar on the left and voice on the right, if I disconnect any of the two returns I get voice and guitar mixed on both left and right

("mixed" means: 6dB attenuation and sum)

if I disconnect both return jacks the send is mono (voice and guitar mixed at the send and going to tip and ring)

- then if I connect a mono TS jack to the Send and two jacks to the returns, I get only the left signal (guitar) at the send,

now if I disconnect any of the two returns (or both) you get voice and guitar mixed at the send

about the levels:

1- in the true stereo configuration (two return jacks connected) each signal (guitar and voice) do loose the infamous 5dB

2- in the mono summing situation (only one return jack connected) the signals which arrive at the fx loop block inputs are attenuated by 6dB, they are summed and then they loose the inexplicable 5dB so I read -11dB for each signal

3- if instead of two different signals (guitar and voice), I send the same signal (input setting: guitar/same) to the fx loop block, in mono or stereo configuration the only loss is the 5dB inexplicably introduced by the send jack.

4- with the fx loop switch set to "line" all the tests give the same results, but all sends are boosted by 12 dB's



Re: What every POD HD 500 owner *REALLY* needs to know!
by Ed_Saxman on 2013-01-24 05:25:42

Hi fellas!

Just my two cents. I´m using a RC-300 Loopstation (that has a clip peak led) with the HD500´s FxLoop switch set to line in the true stereo configuration (and FXloop last in the chain). I usually need to set a range between -6 and -24 on FXLoop Send parameter to prevent clipping the RC300´s inputs. This varies depending on the initial input source (for instance, changing the bass model on my Variax Bass 705 I may need to adjust that parameter, since different models have slight volume differences)

Besides that, I usually set the parameter Return to +12, to get back comparable volume coming from the Loopstation, and the Mix parameter set to 50% (which seems to give 100% of both sources). Finally, I use the HD500 S/PDIF Out going to my sound card.

Of course all this doesn´t mean anything, just my personal experience when using both units together.

But I'm glad to see what I was doing "by ear" so far, is pretty much the same than the "line, send: -7 , return: +8" or "line attenuated" solution by Lorenzo.

As he wrote:

- set the fx loop switch to line

- set the send to -7 dB and the return to +8dB (could be e.g. -6 / +6 on different machines)

now you have a unity send and a unity return AND you can boost or attenuate both if you need it!



Re: What every POD HD 500 owner *REALLY* needs to know!
by hurghanico on 2013-01-24 05:32:17

perapera, considering the results of your concrete tests it seems clear that those missing 5 dB should be considered definitely a bug



Re: What every POD HD 500 owner *REALLY* needs to know!
by perapera on 2013-01-24 06:53:23

as I said somewhere else,

I think it was made on purpose to have a conservative level to avoid any kind of unwanted clipping

this was a wrong decision made worst by not documenting it anywhere

they should have put a simple control to attenuate OR boost the send AND the return with an indication of the unity level

bye

Lore



Re: What every POD HD 500 owner *REALLY* needs to know!
by perapera on 2013-01-24 06:58:53

Hi everybody!

after other tests, I posted a new discussion about the Looper (not the fx loop!)

it's very connected with the present discussion because it's about signal routing,

but I didn't want to add too much informations on a single page

I hope it will be helpful for someone

bye

Lore



Re: What every POD HD 500 owner *REALLY* needs to know!
by phil_m on 2013-01-24 07:01:15

This may be a dumb question, but why is having unity gain so important? I'm used to running all sorts of pedals in front of amps, and I do try to have it so that the gain staging behaves in a way that makes sense, but I've never been particularly worried that I have unity gain. Actually, I've found that for most tube amps, I like having the input pushed a little harder as a baseline.



Re: What every POD HD 500 owner *REALLY* needs to know!
by hurghanico on 2013-01-24 07:53:29

phil_m ha scritto:

...why is having unity gain so important?...

is not at all important to get unity gain as an end result, but for someone it is important just to know whether you have it or not.. to understand why the response of some models or real fx/amp can be too weak, as expected or perhaps exaggerated depending on your choices of routings and other settings..



Re: What every POD HD 500 owner *REALLY* needs to know!
by spaceatl on 2013-01-24 09:29:24

"unity gain" is a misused term in this context and many others...much like "true bypass"...Most of the folks using these terms don't really know what unity gain is or the real implications of true bypass...but hey, they sound good...makes me feel smart when I use them...

reminds me of these other false absolutions...

Class A is better than AB...it's an A right? The B means, not as good as A...

and there's the notion that "signal must be balanced"...most folks don't realize that means a -6db loss in headroom...But hey it's balanced...that must be better right?



Re: What every POD HD 500 owner *REALLY* needs to know!
by meambobbo on 2013-01-24 11:31:23

I just got a unity gain, true bypass pedal.  it's amazing. it's the most transparent piece of gear i've ever owned.  you'd swear it's like it's not in the chain at all!



Re: What every POD HD 500 owner *REALLY* needs to know!
by silverhead on 2013-01-24 11:34:41

Is it so transparent that it's invisible?  Were you surprised when you opened the box and saw nothing?



Re: What every POD HD 500 owner *REALLY* needs to know!
by meambobbo on 2013-01-24 11:57:17

Indeed!  You don't even plug any male 1/4" jacks into it.  You take an existing 1/4" cable already connected to other gear and just set it on top of the cable.



Re: What every POD HD 500 owner *REALLY* needs to know!
by spaceatl on 2013-01-24 13:51:27

nice one...

I am going to listen to it with my "Turbo Charged Digital Ready" headphones....The noisefloor was so quiet that I ended up 6 hours in the past...



Re: What every POD HD 500 owner *REALLY* needs to know!
by perapera on 2013-01-25 06:58:58

there are no dumb questions, Phil

just dumb answers ;-)

Knowing where unity is, is just an information: if you know where you are, you can decide where to go

if I connect the pod HD with the 4-cable method,

when I bypass every effect in the section of the pod between input and send,

I want to hear at least the same gain as if I was connected the guitar directly to the amp,

does this make sense to you?

(it does to me and many people on this forum)

if I loose 5dB in that section I want at least that the manual informs me about that!

and to spaceatl, could you please explain where the term unity gain was misused "in this context"? thanks

bye

Lore



Re: What every POD HD 500 owner *REALLY* needs to know!
by phil_m on 2013-01-25 07:25:17

if I connect the pod HD with the 4-cable method,

when I bypass every effect in the section of the pod between input and send,

I want to hear at least the same gain as if I was connected the guitar directly to the amp,

does this make sense to you?

It makes sense to some extent, but I don't know if it's really that big of a deal. If someone is really concerned about the level they're sending to their amp, they can always flip the line/amp switch to line, turn the master volume down, and make up the gain that way. I just think it's very easy to miss the forest for the trees in these discussions. I think it comes down a lot to the type of players who are using the POD. Personally, I've never been the type of player who's thinks the tone of plugging the guitar straight into the amp is something I aim for. I always have at least one pedal on, so I'm always "messing with" my tone. I'm less concerned about what the pure tone should be, and more concerned about getting the tone I want. And franky, I think the people who really are tone purists probably would have written off something like the POD a long time ago.



Re: What every POD HD 500 owner *REALLY* needs to know!
by MartinDorr on 2013-01-25 07:41:19

Contrary to Phil I am very interested in a tone w/o or with very little effect. But despite that I think Phil is on to something very important: It's the result (the tone you want or achieve) that counts. Along those lines I am only interested in the level discussion and do my own measurements to avoid running the HD500 in a mode that prevents me from leveling different tones and that runs individual effect or amp models on or beyond the margins of its intended operation (due to too low or too high signal levels). Obviously, you can live in the margins and enjoy the result, but it is unlikely that you can predictably adjust such a tone so it works together with other tones or for different venues. At the end of the day I need to get some predictability in how to make my stuff fit in the world I am playing in (and the world is changing even if I just play in my home: sometimes my wife is home and sometimes not ;-).



Re: What every POD HD 500 owner *REALLY* needs to know!
by phil_m on 2013-01-25 07:52:01

Please note, that I'm not saying that I don't think it's important to understand how things are working, although, for some players, I think they are happier just plugging a cord in and being lilke, "and then the magic happens! ". I just think there's a line between spending too much time on analysis and not enough time, well, playing guitar. I guess it's something I've learned from being involved in multiple bands and groups through the years. The times when I'm happiest as a guitarist is when I'm playing with other people, and at the same time, those times are usually when I have the least amount of time to worry about the technical things like this.

I just know that sometimes seeing all these diagrams and technical discussion can scare people off. I don't want anyone to see these threads and walk away from them thinking that because of them that the HD500 is really difficult to use. I think on it's surface, it's still pretty easy to set up and use. And I think there's a lot of useful info in these threads. But at the end of the day, it's about people getting the tones they want out of the unit.



Re: What every POD HD 500 owner *REALLY* needs to know!
by perapera on 2013-01-25 07:57:47

sorry to understand that you didn't even read the first post of this thread...

flip the line/amp switch to line, turn the master volume down, and make up the gain that way

was the solution I proposed in that post

unfortunately the line position seems to have some problems and adds hiss to the signal (see here)

purist? this is the pedalboard I'm working on (click to enlarge):<a target=new href=http://dl.dropbox.com/u/8875989/Pod_HD_forums/perapera_pedalboard.png" class="jive-image" src="http://dl.dropbox.com/u/8875989/Pod_HD_forums/perapera_pedalboard.png"/>

I'm definitely no purist, don't you think?

I don't even have a guitar amp, I play normal and baritone guitar into an AMT valve preamp into a linear power amp and bass cabinet (and it sounds great with or without the pod)

I just want to know what happens to my signal

and while I was doing some tests I thought someone could be interested here on this forum,

so I posted my results

EDIT: if you're not interested please don't post  here just to say...

...well, that you are not interested :-)

bye

Lore



Re: What every POD HD 500 owner *REALLY* needs to know!
by perapera on 2013-01-25 08:00:49

sorry

I posted my reply while you were posting yours! ;-)

I totally agree

playing is what is all about!!

peace!

Lore



Re: What every POD HD 500 owner *REALLY* needs to know!
by jimsreynolds on 2013-01-25 08:29:02

Don't forget 4CM



Re: What every POD HD 500 owner *REALLY* needs to know!
by meambobbo on 2013-01-25 08:40:36

wow look at that thing.  5 expression pedals.  That's actually pretty clever how you stack the M9 over the Pod HD controls you won't likely touch live.



Re: What every POD HD 500 owner *REALLY* needs to know!
by perapera on 2013-01-25 10:11:30

thanks bobbo

actually one pedal is for volume

but I have another one (not pictured) for the loop level of the M9

so it's 5 expressions and 1 volume :-)

...anyway music is about expression, isn't it? ;-)

for the M9 I just built a wood frame covered with rubber which preserves the pod knobs and raises the M9

still haven't tried it live though

it's quite stable but it may need some velcro over it to make it even more stable



Re: What every POD HD 500 owner *REALLY* needs to know!
by spaceatl on 2013-01-25 14:46:50

These kids are learning faster today, that's for sure...Back in the day, it took me 3 1/2 years of subscriptions to Guitar For the Practicing Musician, Guitar Player, playing and going to every show I could, talking to every guitar player I met and hanging out at the local guitar shop to comprise what I could learn in a week with Google today...



Re: What every POD HD 500 owner *REALLY* needs to know!
by drewfx on 2013-03-05 09:26:30

I just wanted to add something.

flip the line/amp switch to line, turn the master volume down, and make up the gain that way

As a proposed solution to matching the gain stages, this is inaccurate. The difference between line and amp is the impedance - line is a low impedance signal, and amp is a hi impedance signal. Plugging a low impedance signal into a unit expecting a hi impedance signal is going to cause signal loss, extra noise, and increase chances of ground hum. Adjusting the master volume will not account for this, because the master volume is pre-impedance conversion. You'll be turning up the signal sure, but you'll also be turning up the noise.

You would need a DI box after the output if you wanted to use the line setting, to match the impedances.

As for unity gain - unity gain is a pretty simple concept to understand... the level that goes in is the same as the level that comes out. If it isn't... you don't have unity gain.

In my opinion anyway - don't mean to step on any toes, but I don't think the proposed solution is ideal. The better way to do it would be to get the gain staging correct, which seems like it is impossible as Line 6 don't offer you features to truly account for the -5dB drop off in the effects loop.



Re: What every POD HD 500 owner *REALLY* needs to know!
by snhirsch on 2013-03-05 09:54:24

drewfx wrote:

As a proposed solution to matching the gain stages, this is inaccurate. The difference between line and amp is the impedance - line is a low impedance signal, and amp is a hi impedance signal. Plugging a low impedance signal into a unit expecting a hi impedance signal is going to cause signal loss, extra noise, and increase chances of ground hum.

There is no inherent problem with driving a Hi-Z input from an output with low source impedance. The reverse is not advisable due to the potential for a Lo-Z input to "load down" a high impedance source and cause signal degradation (probably an increase in distortion).  In neither case does the impedance mismatch itself have any direct bearing on the level of hum and noise.  That's more likely to be a function of how the connected devices are grounded, whether or not a balanced line is used between them and the relative gain staging. 



Re: What every POD HD 500 owner *REALLY* needs to know!
by meambobbo on 2013-03-05 10:08:22

Just use a studio eq before the loop to boost the signal...



Re: What every POD HD 500 owner *REALLY* needs to know!
by meambobbo on 2013-03-05 10:10:01

There's something to it though. Many reports that line produces more hiss than using amp even after correcting the levels



Re: What every POD HD 500 owner *REALLY* needs to know!
by perapera on 2013-03-05 11:12:45

hi drewfx

1) I see there has been some misunderstanding here

phil_m (not me) wrote the sentence you cited "flip the line/amp switch to line, turn the master volume down, and make up the gain that way"

this could have been confusing because we were talking about the send jack, not the output so there is no "master volume" involved

so, to clarify, the first solution proposed by me (and others) was to use the fx loop switch on the line position and ATTENUATE the sent level with the send parameter of the fx loop block

this solution unfortunately gives back some hiss so of course it isn't ideal

2) you wrote "line is a low impedance signal, and amp is a hi impedance signal"

seems you're still talking about the output stage, right?

where did you get this info?

I don't think the output switch changes the impedance at all;

it could be that the fx loop switch has hi-Z on the stomp position but I can't find any line6 official statement about the send (nor output) jack impedance

anyway as snhirsch stated above, the "low-Z out to hi-Z in" connection in theory shouldn't create the hiss problem

3) the second solution to the 5dB drop of the fx send is to use the stomp position and use an fx block as a boost before the send

this is not ideal too because you loose an fx block

...well I guess we can say that the pod HD itself is not "ideal"

but in the end I actually chose this solution even if I loose an fx block (I use a tube comp with threshold 100 and level 17); and by the way I decided NOT to compensate for the +4dB given by the return circuit or I would have to loose another block

please read this post for a complete explanation of problem and solutions:

http://line6.com/support/message/406077#406077

bye

Lore



Re: What every POD HD 500 owner *REALLY* needs to know!
by drewfx on 2013-03-05 13:22:59

Heya Lore,

I just wrote a whole response, and this bloody forum lost it! Garbage interface was also responsible for me misquoting you. I knew it was Phil I was responding to, but for some reason it didn't quote him properly. Don't know why, sorry about that! Anyway...

All of what I'm about to say could be complete balderdash, but here is my take on it:

The main outs can be switched from Low-Z (Line) to Hi-Z (Amp) using the 1/4" output switch on the top of the unit. Are you saying that this switch doesn't adjust the impedance, and only adjusts the output level?

Likewise with the FX loop, it has its own Low-Z (Line) or Hi-Z (Stomp) switch. So logically (if these switches do switch the impedance) you'd set them both to the Hi-Z (Amp and Stomp) setting for a 4CM setup with a guitar amp.

Going from Hi-Z to Low-Z will introduce muffling on the high-end (adjusted frequency response) and will also screw with the signal to noise ratio. This is where the extra hiss and hum comes from in that situation.

Going from Low-Z to Hi-Z should be fine in theory, but not all guitar amps are made equal. The Marshall JVM for instance has a 470kΩ input. The Fryette Sig X has a 1mΩ input. That's a pretty big difference. The PodHD500 has a 1mΩ input impedance too, and AFAIK this wont change when turning the guitar input pad on - although it can be adjusted from within the setup I believe.

I cannot find figures for the output impedances, but it would be easy enough to test with a multi-meter and an exposed patch cable.

Ultimately, as I understand it, there is a difference between output GAIN/LEVEL and output IMPEDANCE. I'd be happy to be shown if I am wrong though.

Quick story: I had a Pod HD500, one of the first ones. At the time I had a Fryette Sig X. No matter what I did, I couldn't get it to stop sucking all my tone - weirdly though, I was losing a ton of low-end, not high-end. Couldn't ever figure it out. Now I use a Marshall Satriani JVM, and I am tempted to try a Pod HD500 out again.



Re: What every POD HD 500 owner *REALLY* needs to know!
by snhirsch on 2013-03-05 14:34:54

drewfx wrote:

The main outs can be switched from Low-Z (Line) to Hi-Z (Amp) using the 1/4" output switch on the top of the unit. Are you saying that this switch doesn't adjust the impedance, and only adjusts the output level?

I cannot find figures for the output impedances, but it would be easy enough to test with a multi-meter and an exposed patch cable.

Ultimately, as I understand it, there is a difference between output GAIN/LEVEL and output IMPEDANCE. I'd be happy to be shown if I am wrong though.

Even without knowing the circuit, I will almost guarantee that the Line/Amp switch affects only nominal operating level (and indirectly, gain) but not impedance.  Impedance is not the same as DC resistance and measuring with a multi-meter is not an accurate way to determine it.  For example, it's common to drive an output through a capacitor and this "looks" like an open-circuit (infinite impedance) when checked with an ohm-meter.   You can loosely think of impedance as frequency-dependent resistance.

Gain, level and output impedance are all different concepts that I think are getting confused in this discussion.



Re: What every POD HD 500 owner *REALLY* needs to know!
by perapera on 2013-03-06 02:44:18

Hi there Drew

yeah I know... I always write the message on a text editor and then copy it to the form...

I really don't know if the impedance is changing with the switches, but I think you don't know either: we are just guessing here.

So my guess is: "No, it's just a -12dB pad on the amp or stomp position of the switches", and that's why:

1) if line 6 spent time and money to design and create two impedance changing circuits they would have advertize it IN CAPITALS just like they did vith the pod input impedance switching system

2) in the 4CM the output of the pod is going to the amp return (or power amp in) wich is a LOW impedance input, so the pod output being hi-z would be a problem actually

3) impedance, in the guitar-to-amp connection, is something that makes the pickups interact with the input circuit in a dynamic and frequency dependant way

so if you put A/D and D/A converters between them it's all lost anyway

the guitar is going to interact only with the pod's input circuit, so converting the D/A output to Hi-Z at the send or output jack wouldn't make sense

(example: ALL Boss pedals have LOW impedance outputs)

---

I'm sorry for you bad story with the pod hd,

if you decide to try it again, and you want to test the input-to-send route bypassing it with a true bypass box, don't forget you have to put in a tube comp (thr 100, level 17) fx block if you want at least the level to be equal to the bypassed signal

[note: I didn't like the Studio Eq in this role, firstly because its gain pot is labeled in dB's but the values are wrong (I found that to have a real 5dB boost you need to see "7,4dB" on that pot), but mainly because, because of its design, it's clipping the signal so you loose peaks; the tube comp is clipping too but in a way that, with my preamp, works better]

I tested the pod for MONTHS before implementing it in my (rather complex) pedalboard

and in the end I went for it for the functionality and not for the sound quality... let me clarify:

the point is that the ability to build infinite strange effects of HIGH QUALITY and to switch easily between them overtakes the fact that I'm loosing something in some of the sounds I use

example: a proco rat into a cranked marshall dosen't sound like the modeled versions in the pod even if I use the same marshall power amp and speakers after the pod

but try to go from there to a complete clean sound and then to a synth sound with 4 delays...

I hope line 6 will create a pod HD1000 with better hardware (input stage, converters, switches,...) and more CPU power, I would pay 1000€ for it, but untill then I'll live with the pod hd 500 flaws

that's my experience

bye

Lore



Re: What every POD HD 500 owner *REALLY* needs to know!
by drewfx on 2013-03-06 05:04:48

Yeah man, I don't know if it does switch the impedances. I naively assumed it would though, since that is what the labelling implies. Bit naughty of them to label it up like that if they're not switching the impedance though - imho.

Do you have the tube comp as the first effect in the chain, or as the first effect after the FX-Loop?

I may just pick one up and see how it sounds with my JVM410JS - which has a fully serial loop, versus the regular JVM's paralell loop.



Re: What every POD HD 500 owner *REALLY* needs to know!
by snhirsch on 2013-03-06 05:13:13

perapera wrote:

I really don't know if the impedance is changing with the switches, but I think you don't know either: we are just guessing here.

So my guess is: "No, it's just a -12dB pad on the amp or stomp position of the switches", and that's why:

Lore,

If you want to determine the output impedance, here's an easy way to get a ballpark:

- Run a 1Khz. tone through the unit and get a usable level at the output you wish to test.  Make sure it isn't clipping. 

- Measure the level at the output using an AC voltmeter or sound card + software that is known to have a reasonably high input impedance.

- Note the voltage or dB level at the output.

- Connect a 100k pot to the output, with the low side of the pot connected to ground and the wiper to the hot lead.

- Leave the meter connected. Start with the pot all the way "up" (wiper away from ground) and slowly turn it down to decrease the load impedance.

- When the meter indicates 1/2 the original voltage - or -6 dB - relative to where you started, disconnect the pot and measure between the low pin and the wiper with a multi-meter on ohms range.  Make sure the output doesn't start clipping from the decreased load. If it does, start over with a lower initial level.

The value of the pot at the point where level falls 6dB (or 1/2 voltage) will be roughly equivalent to the source impedance of the output at 1Khz.  (yes, it does vary somewhat with frequency).  For a typical op-amp output, the source impedance is likely to be very low.  Audio ICs are generally designed to run into non-terminating or "bridging" loads that are much greater than their actual internal impedance.

One common way to implement things like a "stomp/line" switch is to have it change the negative feedback around the final audio stage that drives the output.  On "stomp", it increases the feedback to reduce the gain of the amp and bring nominal level down to a point that floor pedals are happy with.  You can accomplish the level reduction by putting a pad in front of the output stage, but by leaving the gain "high" you run the risk of introducing noise. 



Re: What every POD HD 500 owner *REALLY* needs to know!
by perapera on 2013-03-06 06:12:24

drewfx wrote:

that is what the labelling implies. Bit naughty of them to label it up like that if they're not switching the impedance though - imho.

I think it's definitely not mislabeled and these are the manuals descriptions of the fx loop switch:

"Use the LINE-STOMP switch on the back of POD HD500 to choose between levels for Rack FX versus Pedals"

p. 5.4 of the advanced guide (v.2.10 rev A)

"Set the FX LOOP LEVEL switch to LINE to operate at higher peak-to-peak voltage, making it optimal for line level devices. The loop can also be used with stomp boxes by setting the FX LOOP LEVEL switch to STOMP."

p. 0.7 of the quick guide (rev D)

drewfx wrote:

Do you have the tube comp as the first effect in the chain, or as the first effect after the FX-Loop?

being the send that loses 5dB, the comp is the last block before the send,

but if you are testing the input-to-send route against a true-bypassed signal it should be the ONLY block between input and send,

that's the setup I had in mind:

<a target=new href=http://dl.dropbox.com/u/8875989/Pod_HD_forums/pod_in-to-send_vs_bypass_test.PNG" class="jive-image" src="http://dl.dropbox.com/u/8875989/Pod_HD_forums/pod_in-to-send_vs_bypass_test.PNG"/>



Re: What every POD HD 500 owner *REALLY* needs to know!
by perapera on 2013-03-06 06:13:19

wow!

thanks man,

I saved a text file with your steps to measure impedance, I'm shure it will be helpful to me sometimes

but for now I'm done testing with the pod... now I'm playing it!

thanks again

Lore



Re: What every POD HD 500 owner *REALLY* needs to know!
by snhirsch on 2013-03-06 15:24:46

You are welcome.  Just keep in mind this is a very crude approach :-).




The information above may not be current, and you should direct questions to the current forum or review the manual.