Wah Output Buffer

[GibsonGM]

One thing to consider, and call me a purist if you want...is that every part you put in your signal path takes you a little bit farther away from "the real you".    Now, ok - we all love to have our Ge's for fuzz, even optoisolation for other things but - my theory is that if it's not needed, then DON'T put it in there!
I've built overly complex stuff, loaded my chain to the max, and really dug it. Then I go back to guitar >>amp  or guitar >>booster>>amp, and LOVE that too!

My feeling about an un-needed output buffer is that it is going to rob you of that much more of your original tone.  Input buffers are often needed to compensate for the low Z of NECESSARY processes (like a mid-scoop Pi network or something)...rarely are output buffers needed for the things we do.    But if it rocks your boat, well - go ahead and pop one in there, it's your rig!!   I'd really like an answer to this question, though:  If there is currently nothing wrong with your rig, why do you think you need to put a device at the output of something that works fine?  *shrug*

Side note:  how can ANYONE wah their fuzz?? Isn't that like a mortal sin in some world religions??  ha ha

[joegagan]

agree, for the most part, except i have found that an out buffer is very helpful in isolating the wah circ from bias changes when an out vol is needed. the out vol is needed ( lately for me) as i have found the swampy-swamp tones of modded boomerangs esp cool and heavy but the output level exceeds the bypass volume. lowering the input vol (input R) or reducing gain on Q1 cause a loss of swamp.

[soupbone]

I'm confused!lol

[Gus]

Something to keep in mind
A FF circuit input should be thought of as a summing node.  If the first transistor had gain like an opamp the input would be close to 0 ohms
A BMP input has C to B feedback/bias resistor, however it has a series input resistor this sets the max gain.  Other gain stages with C to B with a feedback bias resistor without a series input resistor might have issues after a Wha.
Note there is another arrangement of parts that adds a resistor and cap to remove the signal feedback from the C to B DC biasing

The gain of the first stage of a FF is partially the feedback resistor / what is before the FF(the open loop gain of the transistor matters)
a passive guitar or bass as the input RLC sets this up in a nice range.
Think about what happens when a FF is driven by a low output resistance source
It will increase the first stage gain in the FF

So a series resistor or volume control of the correct value range should work fine

When I see source followers or emitter followers or opamp buffers without a series build out resistor at the output for use at the "end" of a wha circuit I wonder why they are used.
I don't understand why someone would build it if they thought about what they are trying to "fix"

[DougH]

So a series resistor or volume control of the correct value range should work fine

When I see source followers or emitter followers or opamp buffers without a series build out resistor at the output for use at the "end" of a wha circuit I wonder why they are used.
I don't understand why someone would build it if they thought about what they are trying to "fix"

I agree. I don't think the output buf is necessary for solving the FF interaction problem.

In non-technical terms, think of it like this: A fuzz face with your guitar wide open sounds fairly muddy, in a good way. That's part of the sound. The Lo-Z loading etc rolls off highs and smooths it out. The wah cannot "cut" through this mud, so it doesn't work very effectively. It is too rolled off.  But what happens when you turn your guitar volume down a little when plugged into a FF? You get more highs, a clearer sound. The output series resistor on the wah mimics this to some extent. It adds a little resistance, raising the input Z a little. The tone is clearer with more highs. The wah sound is no longer rolled off by the interaction with the fuzz, instead it "cuts through" pretty clearly. A ~50k series resistance is enough to fix this issue with a FF, but with a Hi-Z input like an amp, or another kind of distortion pedal, the effect is negligible. So it doesn't change the sound of the wah.

Don't blindly throw buffers (or any other circuit) at a problem without understanding it first. Figure out what the cause of the problem is, then take the appropriate action to solve it.

[GibsonGM]

Don't blindly throw buffers (or any other circuit) at a problem without understanding it first. Figure out what the cause of the problem is, then take the appropriate action to solve it.

Ya.  A 1K  to 10K input resistor (or higher, by ear depending on the circuit) placed in series at the input jack of a FF solves that problem....the problem lies with the FF, not the wah.

Maybe one day, you try some pedal conglomeration and say "Hey, holy wow - now THAT is what I'm after!!!   My wah before my FF, wah my fuzz, so cool!".   But notice it's mushy or whatever.   So then you correct the issue.    I feel that 99.9% of people would wah their fuzz and say "Yeck!", lol.       I always do put that 1 to 10K etc. resistor in series, tho, just in case they have something they want to try.  To my ears, it is just about transparent vs. it not being there.


However, wanting the buffer to be able to put a volume pot in there without interaction/changing Z - now THAT is a good case of needing supporting circuitry!  There is a clear reason for the buffer at that point.

Just one guy's take on it, tho. YMMV.

[joegagan]

since this has turned into a mini-epic, must register my preference here. i don't  care what jimi did, i don't care  how david gilmour this and that, i like fuzz before wah. overdrive before wah. it just gives the wah  a nice thing to play off of in my particular case.

when i run a lot of pedals, i have fuzz face type before the wah and also another one somewhere down the line (usually several other pedals between the wah and downline fuzz),  it fuzzes the processed signal when needed.  fuzzes are cheap, no big deal to put one before and one after the wah for different functions. i sometimes put a phaser and second wah at the end of all that other stuff too. sounds excellent.

[Gus]

It is so obvious what can be done for a FF if you want it after a wha and also to work like a regular fuzz

Add a series input resistor for after the wha and a switch to short the series input resistor for a normal FF input

Oh no did I give something away?
who will add this textbook idea to a circuit for the newest and greatest FF

If you look at the JH FF schematics you can find there is a 1K in series with the input in at least one of them

[pinkjimiphoton]

So a series resistor or volume control of the correct value range should work fine

When I see source followers or emitter followers or opamp buffers without a series build out resistor at the output for use at the "end" of a wha circuit I wonder why they are used.
I don't understand why someone would build it if they thought about what they are trying to "fix"

I agree. I don't think the output buf is necessary for solving the FF interaction problem.

In non-technical terms, think of it like this: A fuzz face with your guitar wide open sounds fairly muddy, in a good way. That's part of the sound. The Lo-Z loading etc rolls off highs and smooths it out. The wah cannot "cut" through this mud, so it doesn't work very effectively. It is too rolled off.  But what happens when you turn your guitar volume down a little when plugged into a FF? You get more highs, a clearer sound. The output series resistor on the wah mimics this to some extent. It adds a little resistance, raising the input Z a little. The tone is clearer with more highs. The wah sound is no longer rolled off by the interaction with the fuzz, instead it "cuts through" pretty clearly. A ~50k series resistance is enough to fix this issue with a FF, but with a Hi-Z input like an amp, or another kind of distortion pedal, the effect is negligible. So it doesn't change the sound of the wah.

Don't blindly throw buffers (or any other circuit) at a problem without understanding it first. Figure out what the cause of the problem is, then take the appropriate action to solve it.

+1 totally agree.

to me, it's kinda like... ok... gonna add a stompbox that doesn't really do anything useful just cuz i can.

if you NEED a buffer somewhere, (like when ya kick in that third dirt box and the volume thins out or something) by all means use one.
sometimes a buffer will bring the interaction to life.

but not with a fuzz, and not just fuzzfaces.

to me, i can always turn my guitar down if i need to when using my wah, and i prefer to be able to wah my fuzz instead of fuzz my wah. fuzzing my wah is too subtle and doesn't work as well FOR  MY style.

[pinkjimiphoton]

since this has turned into a mini-epic, must register my preference here. i don't  care what jimi did, i don't care  how david gilmour this and that, i like fuzz before wah. overdrive before wah. it just gives the wah  a nice thing to play off of in my particular case.

when i run a lot of pedals, i have fuzz face type before the wah and also another one somewhere down the line (usually several other pedals between the wah and downline fuzz),  it fuzzes the processed signal when needed.  fuzzes are cheap, no big deal to put one before and one after the wah for different functions. i sometimes put a phaser and second wah at the end of all that other stuff too. sounds excellent.

i agree and do the same. my guiitar hits my octavia, then my fuzzface then my tuner then my wah. from the wah it hits a super overdrive, a diphonizer (bean's honey dripper) my suzy q,  a dano french fries auto wah, then the super hard on, my gate (actually everything after the face is in the loop of the gate) then it hits the korg mr multi, , clone theory , flanger, multi mod (google up the nux mod force .... hard to beat for what it does... two independent modulation engines WITH tap tempo for about 60 bux shipped...and the time force delay is even better) and delay. sometimes i add more.

but i'm running a wah and two autowahs, and the mister multi is a wah too... and have fuzz first, then distortions, then overdrives, seems to give me the most controllable natural sounds.

multi wahs and multi fuzzes rule.

[jalmonsalmon]

I installed a new smooth wah pot from Joe and the Terrible Terriod inductor with great results using his suggested widening sweep trick and now have a sweet vocal sounding wah wah.  But I can see what Joe is talking about with use of a buffer to control the wah wahs output since now my wah is really LOUD and exceeds the bypassed signal. I have a home made foxrox retrofit that sort of solves the issue but I still need to test everything in a band situation at band level so see how the wah wah acts with my setup and effects. I put the wah in front of a fuzz face and if I turn my guitar volume down a tad it sounds great that way and when I need the insano wall of madness I hit a pink flesh and that sends everything into a frenzy 

[CodeMonk]

Good stuff guys!I think i will add an output buffer to mine using fuzz central's layout;http://fuzzcentral.ssguitar.com/mccoy.php It has a 100k trimpot for the "volume drop" after making it true bypass.I could "adjust" the volume drop by changing the 68kr by making it 47k,but this one is an original 1st issue dunlop crybaby.The only thing i wanted to do is make it true pass with a carling dpdt switch.Plus,i'm probably gonna build me a fuzz soon.

I added that output buffer to my Crybaby.
Made a difference but still not perfect. But it did make it better.