MartinDorr

I can't go into depth right now, but feel welcome to ask specific questions (including the PDF file). The PDF is a collection of data I collected over months. I grabed all my floating sheets and added a couple measurements I did not use and put the PDF together over the last 2 days. In regard to your posting above I am not clear whether you use LVM or not. I have no data or advice for LVM and it is probably quite different from the 'full amp' as it is a modelled power amp running over some unknown 'real power amp' out the DT speakers , i.e., in simplified terms your hear the power amp portion of the full models in the HD running through some neutered real power amp stage of unknown type. One thing I don't get is your comment that your HD headphone signal is level for the different amp types. This makes no sense to me as the output of the HD must be different to cause level output on the DT if you utilize different power amp configurations. Maybe I am missing something. You can't flip the Path A and B configuration I described in my document because the Amp in path A drives the power amp configuration of the DT (this is hard-wired). No Amp in path A and the DT is using it's own channel B setting and the builtin DT preamps. If you want to deviate from what you can configure as power amp section in a single amp tone (e.g. to control Presence of the power amp independent from the preamp) you must put a (muted) power amp configuration in path A and the preamp of choice and its settings in path B (in this case Path A is muted in the mixer because its only purpose is to configure the power amp stage in the DT). Obviously you can also use this setup as a full dual amp patch by letting the Path A signal (partially) through. Hope this makes sense, Martin

CH VOL just brings the output level of the selected amp model into a healthy range (it does normally not change the sound), especially low enough so that the signal does not compress or even clip (you may even be happy with the former but probably not with the latter). If you can measure your amp output signal (e.g. via USB) I'd recommend to stay with peaks below -12dBFS if you want to avoid soft compression. No problem going higher if it pleases your ears. As said by bjnette, the POD Master just controls your final output. Good to adjust for venue (don't change if for different tones as it is not stored with patch. I run mine typically at 9 o'clock for quiet practice in a small room and 12+ o'clock if noone's home.

I posted on the DI thread a 2 page document describing the 'secrets'. In a nut shell: Even though some preamps claim to share a common power amp configuration (e.g., voicing I, class A/B, pentode) they select 1 of 2 amplification levels and on top PRES values > 50% also have impact on level (and naturally tone). This is interresting to understand when and why corrections to produce leveled tones are necessary. The above can also be used to tailor custom 'dual amp' tones where path A is simply selecting a power amp configuration and independent power amp PRES setting, while path B is used to dial in your pre or full amp model with full tone stack, ER, mic, and cab controls. Hope the 'nut shell' was big enough to summarize what the doc is about. The details are described here DT25 Power Amp Parameters.pdf Martin

I posted on the DI thread a 2 page document describing the 'secrets'. In a nut shell: Even though some preamps claim to share a common power amp configuration (e.g., voicing I, class A/B, pentode) they can in some cases select 1 of 2 amplification levels and on top PRES values > 50% also have impact on output level (and naturally tone) of the power amp stage. This is useful to understand when and why corrections to produce leveled tones are necessary (even though it may only get you in the right ball park). The above can also be used to tailor custom 'dual amp' tones where path A is muted and just selects a DT power amp configuration and a preamp-independent power amp PRES setting, while path B is used to dial in your pre or full amp model with full tone stack, ER, mic, and cab controls. Hope the 'nut shell' was big enough to summarize what the doc is about. The details are described here DT25 Power Amp Parameters.pdf Martin

I already commented in the DT Amp forum how bad this behavior is. Not sure whether it helps anything, but you may be able to use the attached doc to shed more light on which Amps produce same amplification levels including info on how PRES settings can change the level even if the selected Amps are using the same class, voicing, and tube configuration, i.e., not all preamps selecting the same power amp configuration are created equal. Seems the DI feature is pretty useless for live performance situation (unless you limit yourself quite a bit or are really quick to switch more than 1 knob/dial). Good luck, Martin

Check your MAC audio settings and Garageband master and track settings and make sure everything is at 0dB gain. Use an HD tone (empty) with no effects and no amp (or bypassed) with mixer at 0dB gain, input 1 Variax, input 2 Aux (nothing connected) Set your JTV to Spank 1 and you should see a input meter level of less than -15dB Peak playing a single note melody line. Once you have this or a similar baseline you can add effects/amps and make sure your are not exceeding -12dB peak to avoid model compression/distortion. Every model has output gain (channel volume on amps). If you dial the input gain/drive up, dial the output gain down to stay below -12dB. Going a little above is OK, but don't go too far if you want to avoid soft compression and other effects the models throw at you when the peaks hit -6dB or higher. Good luck, Martin

I use the mixer strictly at the end of all processing. For single Amp tones I put all models in 1 path, mute the other path, and use the mixer only to adjust for power amp configuration volume differences. I believe to remeber that in this case channel panning in the mixer does not matter. If you split the path with an Amp and then mix both paths center you just get a 6dB boost versus if you just keep them on each side (or use only 1 path in the center). I believe the volume difference between the quietest and loudest DT25 power amp configuration is close to 20dB (4x volume difference), i.e., when you had +7 and -7 dB in the mixer to adjust volume and used center pan (+6dB) you hit it right on correcting for a 20dB difference. I have more detail on the relative volume levels the different power amp settings cause (and 2 little HD500/DT25 communication 'secrets' that I think exist, but they usually don't matter much in practice when you just fiddle with the knobs until you like what you hear). Let me know and will find my notes and post. Martin

I played around with this topic quite a bit and came to the following conclusions: If you have any DAW or other measurement equipment, try to figure out what your HD500 input signal level is for every guitar you use for line, double stop, and chord playing. You can do this for example with a fully split path A and B w/o any effects or amps and measure via USB. Set input 1 to what you need and input 2 to something you don't use (Aux is lowest noise). Mute path B in the mixer, just to be sure that there is nothing coming through. Aim for a peak input signal level that does not exceed -12dBFS. Lower pickups, adjust variax string volume, turn Volume pot down if you have to, ... In most cases you will be lower, write the number down for future reference so you know how much you can and probably should boost for optimal signal level through the HD models. If you are at -18dBFS or lower you can savely use Same for input 2 and go into a mono effect or amp. If you do, you will get in effect a 6dB boost. I have no personal experience that there is a phasing problem, but that could be because I can't hear it or because I use a Variax, or ... (lot's of possibilities). My point, there are other ways to get a clean boost (and usually a fixed 6dB is not what you'd want anyway), but if it works for you then there is nothing wrong using the 'Same' effect to boost. One word of caution. You may be using the looper in preposition to replay a recorded signal for different measurements. This is working really well IF you consider that the looper may play everything back about 6dB lower than the original input signal. It does not reliably do this for me, so I always check the max level of my recording to the level the looper puts out. This is crucial if your looking for how much you can savely boost because the looper may make you believe you have 6dB more head room. My experience is that my live signal is usually 6dB hotter. Good luck, hope this helps a bit. Let us know whether it's useful. Martin PS: My JTV-69 Lester Pos 1 comes in at about -12dBFS for playing single lines. Any hard strumming moves it close to -3dB, which is way to hot for compression/distortion free effect and amp model playing. My approach is what you'd do on stage: Turn the Volume knob down ;-).

I don't remember popping sounds w/o changing topology/class/tube type, but I do know that changing the preamp on my DT25 (while keeping topology/class/tube same) will change some additional behaviors in the power amp stage. For one, it seems the that the Presence setting will have an impact and that different preamps select different baseline attenuation levels for the power amp stage. You can check this out by putting the a preamp into path A and nothing into path B. Then set the mixer of path A to Mute and Path B to 0dB center. Now you should hear a pure power amp stage amplification of your input signal going through the HD w/o any processing through path B. Start with a Type I, A/B, Pentode preamp. Chaning any of the Drive, Bass, Mid, Trebble, Channel Volume dials will have no effect, but Presence does. Raises your level about 3dB and changes frequency content, i.e., Presence is used in the power amp stage. Now try different Type I, A/B preamps. You will find output level changes of about 8dB from the lowest (I think FlipTop) to the higest (Hiway). I have not dug deeper into whether after you adjust for the volume differences (via mixer) that there may also be significant tone changes. I'd guess at least minor changes because the RMS level do not track the peak level differences, i.e., there is some harmonic content added or removed when selecting to different preamps. But remeber, this experimental patch does not use any preamp model. Neither in the HD500 nor in the DT25. Back to the popping. I don't remeber hearing poping when I experimented with all the above, but I may just not remember and things do change in the DT power amp stage even if you stay with a fixed class/topology when you change preamps. Also, I was using the HD to experiment and not the edit SW. I may be able to dig up an old list of measurements and can post level differences if you are interrested. Not sure whether that translates between DTs as I guess tubes and biasing may have impact on the magnitude of differences. Martin

Thanks, Seems like a slow process and probably pretty biased towards ones own preferences. Will report when I have something that others may find useful (to avoid).

Looking for advice on how to balance string levels on a JTV-69. I understand there is a global and a per guitar model control. Assuming one would start with getting the global setting right, what guitar model should be picked? Any other advice on how to go about doing this would be great. Martin

Are you sure you have the looper in post position. The pic in the display shows what it will be when you push the button and not the mode it is in. I understand that you have though of that before, but i fell for it several times in the heat of having fun. If this is not it the only thing I can think of is a broken foot switch. Good luck.

Just 3 questions you may want to check in before you send it all back. 1. Did you or the store you bought it from change or 'setup' the magnetic pickups to be very high? If yes, you may want to lower them because if they are very high you may get warble and other side effects from the magnetics even if you don't use them. 2. Did you change the overall volume of your piezzos by accident in the workbench. If yes, oh well, you know what to do ... 3. Make sure your battery is fully charged. This should really not matter as I have never seen your effect due to a drained (on the edge) battery. But better make sure this is not the issue (or the battery is just bad). If none of the above, I'd also say your JTV is broke like Charlie_Watt did. Good luck.

Just came back from a trip to Guitar Center in Tempe Arizona and they had a single L2t for $600.- as a 'special' and supposedly a few more in the distribution channel.

I started there as well expecting no distortion and/or compression till the signal clips. This is NOT how it works. Any model I checked (all preamps and a few effects) shows the same behavior. If the combination of input signal level and model setting causes an ouput level above -9dBFS you can hear in most cases noticable compression and soft clipping. If you measure and compare transfer curves (e.g., how Drive affects output level you can see the effect usually somewhere just above -12dBFS. My conclusion: Unless you want to measure every time, stay away from levels above -12dBFS unless you actually want the effect. I believe you cann boost the signal cleanly above the -12dFS with the mixer if you can live with the mixer at the very end of your effects chain, i.e., single amp / path tones.

You said you checked levels via USB. What was/is the level you see before going into the EQ? If you want absolutely no compression/distortion from Studio or Mid Focus EQs make sure your input AND output peak does not exceed -12dBFS. Other EQs are likely similar. Martin

You want to be aware that this change simply raises the level of the HD output signal (I believe either 3 or 6 dB). Not that this is bad if it does what you need. Just bringing this up so you can raise the output level by other means if in the future you add effects trailing the mixer but they do not sound good with the increased input signal level. Martin

I think the HD internal amp numbering scheme can handle 3 more amp models. Whether they fill it or whether they even have Flash space for more model code is a different story altogether. I am also in the boat of guessing that a new HD product is more likely than a significant FW update.

It may have been lost in the good comments above, but there are 2 types of rotary dials on the HD surface. The large dials for Preamp settings (Bass, Mid, ...) are not relative but absolute in respect to what you see in the editor as parameter value. For example, if your dial is at 12 o'clock and the associated parameter value in the editor shows a 30% value and you just slightly move the dial clockwise the parameter value will 'jump' from 30% to say 51% or 52% depending on how far you turned it. In other words it does not matter much where you leave the knobs. The range of possible change is always the full range. The display shows roughly where the original setting was if you change them. The small dials under the display are used to edit effect parameter and other settings are relative dials with little nodge-like physical feedback when you change them. These dials have no physical min or max setting. They simply change the parameter value either up (clockwise) or down in the units shown in the display. Sometimes they are just different choices and not different values of a parameter, but the display shows you what you currently have. I don't know of any way to figure out what the original value was other than changing the tone and back, but that looses all your changes you did not already save. Good luck. As said before, it's not so complicated as it may sound once you get used to it.

Always preamp models (1, 2, or no preamp at all). All HD internal signal levels <= -12dbFS (checked via USB with HD master at 100%) HD cab and mic models to taste (they are just hardwired EQ/compression models). HD master to adjust volume to venue (around <=50% for home). DT master usually at 2-3pm, sometimes higher, never less.

Mine started doing this a good year after I bought it new. 6 months later it just did not work after a power on. New tubes and it runs better now than before (and no crackling or poping noises). Not absolutely clear that those things are related, but no evidence to the contrary either. You decide. Get new tubes would be miy advice. A matched set of four if you are giging or 2 if you don't mind an occasional down time when they go unexpectedly. Good luck, Martin

New versions of processor driven equipment that run say 20% faster has usually more subtle changes than just being able to do 20% more. For one, all things it does are done 20% earlier and that by itself could remove soundartifacts created by delay, e.g., although a faster digital processing step produces the same result, it may provide that result a few clock periods earlier and when this happens with a couple of things that are supposed to 'run' in parallel (but really are done in sequeunce) the outcome of summing signals will be sightly different. To sum it up, there is no such thing as 'just +20% DSP'. There are other effects at play and it seems a careful listener can pick them up.

From my point of view I would consider that you are sending a digital signal to some analog amplifier (DT or L series speaker), i.e., reducing the digital signal only to then amplify it more at the anlog end will always add noise from the analog amplification system to compensate for the digital signal reduction. So the question becomes do you want that 'noise' or do you want to avoid it. In the DT's you probably want the 'noise' because that tube goodness is only showing up if you crank that amp to some degree of your liking. On the other hand, on the L's you probably do not want any 'extra' noise and amplify just as much as needed for an unreduced digital source. In other words, try HD Master as low as needed to work with a fixed Master on the DT and use 100% HD Master and with a variable Master on the L's. I don't have L's to try. So this the above theory and Silverhead has advice based on practice. But trying all your options won't hurt. Martin

Yes, agree, ... and I take that effect as a given. But describing it the way they did invites overdriving the output in an attempt to get the best possible signal-to-noise behavior rather than simply stating that Master should be set to achieve an output signal level with reasonable headroom (probably somewhere between -12 to -6 dB peak) to maximize signal-to-noise performance while not introducing compression or even distortion of analog components in the subsequent signal path.