Impedence for long series of pedals / tone sucking

[Primus]

I recently modded my deluxe memory man so that I could pick a nice balance between additional ouput gain and impedence. I really liked the mod and found the pedal loaded down my pickups less when using the pedal by itself. I've lurked in the forums and understand a bit more about imedence now and especially how it can be detrimental to the proper operation of a wah. This got me thinking though... I have about 12 pedals and sometimes I use them all together. I would say half of them have nice BOSS style buffered inputs etc but what about the others? How can I make sure they aren't loading down my signal and sucking all the tone out? Is this even an isse?

[amz-fx]

I would say half of them have nice BOSS style buffered inputs etc but what about the others? How can I make sure they aren't loading down my signal and sucking all the tone out? Is this even an isse?

if they are not buffered then they need to be true bypass.  Otherwise you may have a tone sucking problem.

http://www.muzique.com/lab/main.htm

regards, Jack

[Mark Hammer]

The question you always need to ask yourself is "What lies in the path between my guitar and pedal X?".  Follow that one with "What lies between pedal X and my amp?".

If there is always something "on" between your guitar and pedal X that accomplishes the needed buffering to counterat cable capacitance and other nasties, then your concerns about pedal X can be reduced or even eliminated.  If what is "on" between the guitar and pedal X also includes any older or poorly planned effects that only use SPDT output switching (loading down the guitar as a result by always having something hanging off the input), then pedal X may need to take special pains to compensate for that, or the situation may demand (as Jack rightly suggests) a changeover to true bypass switching for the offending pedals.

Tone-sucking can occur for a variety of reasons, but the most common ones would be:
a) The results of cascading many many DC/bass blocking caps that shave off your bass a little bit at a time but a whole lot when added up.
b) Loading down of the guitar signal by means of many paralleled resistances-to-ground, topped off with longer cables that only make matters worse.

If your guitar-to-first-pedal cable only "sees" a single pedal with an always-on high-input-impedance buffer, then that first cable will have no audible impact on tone unless it is a very very poor one (say, a 50ft badly/barely-shielded 200pf/ft curly cable).  If there is always something providing a low-impedance out between the last thing in your pedal chain and the input of the amp, then the last cable will provide no audible impact either.

That something *doesn't* "suck" tone is no guarantee of a pristine signal.  Individually, those FET-switched-and-buffered boxes are quiet enough.  Added up, they can add audible hiss in some contexts.  If it's a noisy gig in a big hall with a constant din and very loud music that rarely gets soft, it's not a problem.  If it's soft jazz gig in a very quiet room/club, or a recording studio, then the cumulative hiss can be a bit of a problem for some.  There, it is probably useful to have some sort of loop selector that leaves a buffer always in place (which could be your first pedal in line), but surgically removes everything else from the signal path when it's not in use.  The loop selector is also useful because if you want to make setting changes with any toggles you may have installed, you won't have to subject others to any possible popping noises.

[jimmy54]

I was running about 12 true bypass pedal in series and knew I was getting high end loss.  As I had made a true bypass loop box, I built the AMZ super buffer using Hiulbi's layout.

http://www.diystompboxes.com/smfforum/index.php?topic=30917.0

I put all the pedals into the loop and switched between guitar straight into amp and then through all the effects.  With all effects off there was a huge (obviously) loss of treble, clarity yada-yada.

I then put the super buffer into the chain in the loop.  Now when switching between guitar staright in or through all the effects, there was a barely noticable change in the tone (maybe there was an ever so slight increase in treble when going through the buffer, but as I said, there was a barely noticable difference).

Doesn't really answer your question, but maybe if all your true bypass pedals where in a loop together, you could use a buffer with them.

[Mark Hammer]

How pedals behave individually can sometimes be separate from how they behave in combination, and especially big combinations.  Similarly, how a cable behaves on its own is different than how a cable might behave when daisy chained to several others, linked only by jacks and plugs.  One needs to be strategic in planning out a pedal board and the various switching/buffering options.

This is one of the reasons why I frequently recommend a loop selector box as a good first project for newbies.  It's simple and cheap, and if you love pedals I doubt it will ever outgrow its usefulness.

[stumper1]

How pedals behave individually can sometimes be separate from how they behave in combination, and especially big combinations.  

I second that.  I have noticed that even the order of the same pedals can cause them to behave differently - even when all off/bypassed.

There was a thread w/a post by Brian Wampler where he did some audio clips of different buffer/bypass set-ups.  Very well done testing and quite interesting.  Time to search....

[sta63bmx]

YES, the order is wacky sometimes.  My pulsar build was actually very quiet.  There was a little bit of LFO noise if it ran into high gain, but nothing really bad unless the gain was really cranked.  But it had to come last!  If it came early in the chain, once the depth pot was about halfway up or more, it would pop with every cycle of the LFO.  I never figured out why.  It must have been what kind of impedance it was running into, somehow.  I liked the tremolo ok, but I could NOT make that dang pop go away, so I went ahead and set it aside for parts.

I don't run more than maybe five pedals (all true bypass except sometimes a GCB-95), but even with just ONE pedal (or none!) I greatly prefer the sound when I have a clean boost on.  Even if it's barely above unity gain, the sound just seems so much brighter and sparkly with a Microamp heading up the chain.  I've got a Fetzer Valve build in the pipeline, and I'm hoping it takes care of that for me since I'm currently without a microamp.

[choklitlove]

primus-

are you happy with the way it sounds when you play all 12?  if so, then why would it matter if there was some tone sucking going on?


i run into the same thing with bypass/true bypass.  if i can't even tell, or enough to bother me at least, then i just ignore it.  if it sounds good, that's all that matters.

[wampcat1]

How pedals behave individually can sometimes be separate from how they behave in combination, and especially big combinations.   

I second that.  I have noticed that even the order of the same pedals can cause them to behave differently - even when all off/bypassed.

There was a thread w/a post by Brian Wampler where he did some audio clips of different buffer/bypass set-ups.  Very well done testing and quite interesting.  Time to search....

I think this is the link? http://www.indyguitarist.com/soundclips2/TB-demo-306.mp3

Glad you enjoyed it.

bw

[Satch12879]

Having the proper amount of drive current, often forgotten, is also extremely important as well.  Low impedance is meaningless without it.

[Primus]

I was sort of happy with it for a while and then I pulled a pedal out and said "so this is what I've been missing!". Now I am dodgy about every pedal in there and wanted a quick way to know whether or not I had any bad apples. People often ask in here if there is a simple way to check for tone sucking but it seems you need a singal and sweep generator. I should really test capacitance on my DIY cables... Also, I should make sure no signal is leaking to ground. Is there a good way to do this w/ a little circuit so I can put it in a box or should I just use a DMM?

[wampcat1]

I wouldn't sweat it so much -- with ANY pedal you are going to lose or add *SOMETHING* to the core tone. TB or not, buffered or not, you'll just need to decide if the loss of tone is worth the handiness of having those effects at hand.

bw

[Mark Hammer]

Brian makes a very sensible point.  As much as it would be sweet to have a priori assurances of accurate tone, ultimately you have to decide with your ears whether the sound at the end of the effects chain is what you were aiming for or lacking in some definable way.  It should also be worth noting that "tone-sucking" is occasionally used in productive ways.  The very use of a 250k volume pot on Strats is **deliberately** intended to provide "helpful tone-sucking" by robbing the signal of what some players consider unattractive high end.