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Stomp, Line, Amp, -10, +4dbv

line-level 4cm unbalanced out fx loop +4dbv -10dbv hd500 four cable method

Best Answer perapera , 16 January 2014 - 08:51 AM

hi optimus_7

 

1) the problem of the level drop at the send is well known on this forum, I did many tests on my pod,

please read here:

http://line6.com/sup...-the-send-jack/

 

2) sorry your assumptions are wrong, there is NO +4dBu nominal level input or output on the pod

all the "line" are roughly at -10dBV and all the "amp" and "stomp" are at instrument level,

while the XLR's are at a (actually hot) microphone level

 

+4 is for studio-grade signal processors

 

3) also don't be fooled by labels, +4dBu, -10dBV, stomp, line, amp, instrument ... are the NOMINAL level labeling

so a +4 OUTput sends a higher level than a -10

BUT a +4 INput (like the return jack) "waits for" a higher level so it's in fact attenuating the input signal (or, more rarely, the corresponding -10 INput is amplifying it)

 

SO

 

when you select "stomp" on the fx loop it's sending a lower level and boosting at the return

when you select "line" it's boosting the send and attenuating the return

this is the normal behaviour of any fx loop (even that of your amp)

 

 

4) "if I change the Unbalanced Out on the POD HD to LINE, my volume drops significantly and the gain doubles..."

that's really weird, could it be power amp compression/distortion?

 

the output switch should attenuate by roughly 12dB on the amp position which is intended to connect to an amp guitar input

the line position should be right for an amp fx return

 

 

the most "correct" starting point settings would be:

pod fx loop to stomp,

amp fx loop to -10,

and pod output to line

 

but experimentation and your ears are the guide

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#1 optimus_7

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Posted 09 January 2014 - 09:01 AM

Hey Line 6-ers,

I've been using the Four Cable Method (4CM) for a few years now with my POD HD500 and a Blackstar HT Stage 60 amp.  It's been quite successful, albeit after some very careful tweaking.

I've posted a video with the results on my youtube channel if you would like to view it for some context: Click Here

Essentially it details a disparity between the "Guitar In" jack and the "FX Send" jack. With all things in the signal chain being set to Unity - no FX blocks and Amp Mods on Bypass - The level coming out of the FX Send jack is -2.8dB LOWER, on average, than the source signal.  I tested this with a signal generator, recording the level over time, averaging it out.  Then putting that signal through the POD HD500 and out the FX Send jack, recording the level over time, averaging it out - and you see the -2.8dB difference.  This is consistent across any of the settings for the FX Loop Level (STOMP/LINE) meaning that the issue is not related to that level - it's internal.

About 2 years after I did this in-depth analysis - I haven't seen any changes in the firmware that fixed this quirk, but I did start playing with the FX Loop Level switch and the Unbalanced Out switch - which don't make any sense to me.

My questions to the Line 6 Folks:

1 - Is the 2.8dB DROP from Guitar In to FX Send deliberate - or is it a bug?  Or is it because I'm using a TS cable to go to ONE amp instead of a TRS->TRS cable?

2 - Can you help me (all of us) make heads or tails of the STOMP/LINE/AMP settings with Unbalanced Out, and FX Loop - the only number actually given is the LINE level for the Unbalanced out.

From what I've read of the manual:

Unbalaced Out:
AMP = +4dBv (this is assumed because the only number given is the LINE setting of -10dBv)
LINE = -10dBv

FX Loop:
LINE = +4dBv (this is assumed because the manual says "higher peak-to-peak voltage, making it optimal for Line-level devices")
STOMP = -10dBv (this is assumed because LINE was assumed as the +4dBV)

I HAVE to be reading this incorrectly - does higher peak-to-peak voltage mean -10dBv? - why would the 2 LINE settings be different?  I do know that BOTH -10dBv and +4dBv are LINE-Level, one is for Pro audio application, and the other for Consumer application.  Should all 3 of my levels be set consistently?  (All at -10 or all at +4?)

Currently, my setup is as follows:

Unbalanced Out set to AMP(+4dBv), FX Loop set to STOMP(-10dBv), and my amps loop is set to -10dBv.

The Result is Loud and clear sound from the amp - but it can be a little noisy, lots of digital background white noise (probably due to dirty power in my old house - so, not faulting L6 for that.)...I can barely turn it up past 2 or it's blowing my ears out.

So that means that my amp and the FX Loop are both running at -10dBv, but that the FX Return on my amp is getting a +4dBv from the Unbalanced out of the POD.

If I change the Amp's FX Loop to +4dBv - very subtle change, if any at all...hardly noticeable, same thing if I change the LINE/STOMP FX Loop on the POD HD. HOWEVER if I change the Unbalanced Out on the POD HD to LINE, my volume drops significantly and the gain doubles...my clean amp channel sounds like a dimed AC30.

I'm hoping this Real-World example is a helpful analysis for everyone - I'm stoked about my setup and it's super easy to gig with - This is more of an intellectual exercise for fellow nerds like me.

Rock.


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#2 Buckethead85

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Posted 11 January 2014 - 05:55 AM

Thank you for all the informations, you are very kind to share your experience with all of us and they are extremely useful.
I use the 4cm with a laney cub12r which i mic in live situations. I noticed some sort of volume drop but never did any test to verify this.

Some questions:

Do you set the master level at maximum?
What do kind of advice would you give to me to improve my set up? Upgrading the amp with one with more wattage?

thank you again


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#3 perapera

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Posted 16 January 2014 - 08:51 AM   Best Answer

hi optimus_7

 

1) the problem of the level drop at the send is well known on this forum, I did many tests on my pod,

please read here:

http://line6.com/sup...-the-send-jack/

 

2) sorry your assumptions are wrong, there is NO +4dBu nominal level input or output on the pod

all the "line" are roughly at -10dBV and all the "amp" and "stomp" are at instrument level,

while the XLR's are at a (actually hot) microphone level

 

+4 is for studio-grade signal processors

 

3) also don't be fooled by labels, +4dBu, -10dBV, stomp, line, amp, instrument ... are the NOMINAL level labeling

so a +4 OUTput sends a higher level than a -10

BUT a +4 INput (like the return jack) "waits for" a higher level so it's in fact attenuating the input signal (or, more rarely, the corresponding -10 INput is amplifying it)

 

SO

 

when you select "stomp" on the fx loop it's sending a lower level and boosting at the return

when you select "line" it's boosting the send and attenuating the return

this is the normal behaviour of any fx loop (even that of your amp)

 

 

4) "if I change the Unbalanced Out on the POD HD to LINE, my volume drops significantly and the gain doubles..."

that's really weird, could it be power amp compression/distortion?

 

the output switch should attenuate by roughly 12dB on the amp position which is intended to connect to an amp guitar input

the line position should be right for an amp fx return

 

 

the most "correct" starting point settings would be:

pod fx loop to stomp,

amp fx loop to -10,

and pod output to line

 

but experimentation and your ears are the guide


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#4 mrnighthawkcali

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Posted 16 January 2014 - 03:59 PM

I seriously wish I could have found this topic before I purchased the 500X.

 

It was overkill for what I needed, but the price and flexibility with some holiday discounts made it worth the step up from the other older products on the market.

 

I wanted the ability to run FX only with the 4CM, but it's turned into such a complex operation that I'm spending more time tinkering than playing.

 

On to my problem, I decided that I would setup a SetList for 4CM, and another for using the PowerAmp section etc.

 

I found that if I created a blank preset, say Blackface Twin without adding any FX bocks. By simply adding the FXLoop block, the output volume drops. Remove the FXLoop and the volume increases again. This is the case through headphones and through the regular outputs.

 

It doesn't make sense to me that it's not at unity.

 

I'll spend some more time making the tweaks you're suggesting, but I won't enjoy it.

 

 

 

 

 

 


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#5 optimus_7

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Posted 21 January 2014 - 07:20 AM

I found that if I created a blank preset, say Blackface Twin without adding any FX bocks. By simply adding the FXLoop block, the output volume drops. Remove the FXLoop and the volume increases again. This is the case through headphones and through the regular outputs.

 

It doesn't make sense to me that it's not at unity.

Hey man - I TOTALLY agree - I think what's happening, without knowing the particulars of your setup, is that when you add an AMP Block - it engages the amp's "Channel Volume" and that can drop the output.  If you're using the 4CM...It's often best to use the "PRE" versions of the amp models.  It'll still engage the Channel volume - but instead of putting the whole modeled amp (Amp, Cab, mic, etc.) through the power amp section of your amplifier - you're just sending the characteristics of the modeled preamp (Basically - no cab/mic sim.)

 

I've had the best results with that.  Remember to boost your A and B channels on the POD mixer by at least 3dB's.  That should take care of any issues.

 

Let me know if you're having more trouble!  I'm keen to help out.

 

Cheers,


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#6 optimus_7

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Posted 21 January 2014 - 07:32 AM


2) sorry your assumptions are wrong, there is NO +4dBu nominal level input or output on the pod

all the "line" are roughly at -10dBV and all the "amp" and "stomp" are at instrument level,

while the XLR's are at a (actually hot) microphone level

 

+4 is for studio-grade signal processors

 

3) also don't be fooled by labels, +4dBu, -10dBV, stomp, line, amp, instrument ... are the NOMINAL level labeling

so a +4 OUTput sends a higher level than a -10

BUT a +4 INput (like the return jack) "waits for" a higher level so it's in fact attenuating the input signal (or, more rarely, the corresponding -10 INput is amplifying it)

Thanks man - you do know a thing or two.  Great info here...I found this issue 2+ years ago..and it's really great to have other POHD 500 users validating those findings!

 

I wonder why Line 6 isn't fixing the issue - cause frankly it seems like a pretty big mistake.

 

Rock on! 


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#7 optimus_7

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Posted 21 January 2014 - 07:51 AM

Some questions:

Do you set the master level at maximum?
What do kind of advice would you give to me to improve my set up? Upgrading the amp with one with more wattage?

thank you again

 Hey man,

 

Yes - I do set the Master volume at 100%.

 

Set FX loop switch to STOMP (laney Cub uses -10dBv fx loop), Set Unbalanced out to LINE. 

 

Create a blank patch on your PODHD

Turn the Amp mod to bypass.

Put an FX loop AFTER the mixer of the PODHD, and boost the mixer by at least 3dB's (your POD may need to be set be higher or lower..) on channel A and B.

 

Don't boost or cut the FX loop sends and returns...leave them at the default settings (I forget what those are).

 

Don't put any other FX in your patch.

 

Then the best thing to do is to compare your tone - Play through just the Amp (with medium gain) - without a POD - then connect the POD using 4CM, and listen to the sound - if the sound is the same, than you've got the setup right.

 

  • If the sound is the same VOLUME - but the gain is lower, or missing a little growl - then boost the POD mixer a little more - you don't need much - Until it sounds right.
  • If the sound is more Quiet, but has more gain - switch the Unbalanced Out switch to AMP.

Try those settings and let us know how it works!!


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Also tagged with one or more of these keywords: line-level, 4cm, unbalanced out, fx loop, +4dbv, -10dbv, hd500, four cable method

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