Can someone tell my why my DIY fuzz pedal is breaking up in my daisy chain?

[saison94]

I recently ran into a weird technical issue with one of the fuzz pedals I built for a friend, and was hoping someone could point me in the right direction to troubleshoot. The pedal plays fine on my amp and guitar set-up, but breaks up and sounds similar to being starved of voltage on my friend's daisy chain of pedals. His set-up is guitar>wah pedal>Boss chromatic tuner>tube screamer>the fuzz pedal I made>Boss chorus pedal>fender twin reverb amp. When he plugged his guitar straight into the pedal I built and then into his amp, it sounds perfectly fine. It doesn't become glitchy until it's placed in the middle of his chain. We tried inserting it into different stages of his chain, and the only place it didn't break up was just before his chorus pedal. We tried three different power supplies, and got the same result.

It's a typical 9v power supply, true-bypass stomp-switch between clean guitar signal and effect. The first thing the signal hits in the circuit is a 10mf capacitor, followed by 3M resistor to +9 then into the base of the first transistor stage. Very typical fuzz pedal intro. It's actually the Mutantes Fuzz design, if anyone has seen that.

I took the same pedal and placed it in my daisy chain of Boss pedals back at my house and didn't have an issue. Any idea what could be causing this with his set-up? The way he described it was "I think it is to do with the volume input. My SG overloads the input causing some notes (mostly low strings) to start with no volume and then slowly ramp up. Also there are higher notes that are nonexistent."

I'm guessing it's an impedance issue of some kind, but just not sure where to start. Thanks for any advice!

[tiges_ tendres]

It could be the buffers in the other pedals messing with the fuzz.  I dont really play wah, but isnt there something that we do to wahs so they play nicely with fuzzes?

[saison94]

This is the schematic I'm working from : http://media.photobucket.com/image/mutantes%20fuzz/umafloresta/FX/osmutantesfuzz.jpg

I added a gain control on the second transistor, with a 1k pot connected from the emitter to ground. Other than that, no changes.

Are there any sort of changes I could make to the input/impedance to compensate or act as a safety/failsafe against the issues my friend is having with his daisy chain?

[CynicalMan]

The boss tuner has a buffer in it. Try putting the fuzz before the tuner in his chain.

[zombiwoof]

There are two buffered pedals in front of the fuzz, in fact (TS, Tuner), and many fuzzes won't work after a wah unless the wah has an output buffer in it, so he needs to put the fuzz first in the chain.  He can mod the wah with true bypass (if it doesn't already have this) and a typical wah output buffer (which is only active when the wah is in effect mode), in that case he could put it after the wah.  It's common, as others have mentioned, for a fuzz to have problems after stock wah pedals or pedals with buffers in them.

Al

[saison94]

Thanks for the replies guys!

Just wondering, is this symptom of buffering fuzz specific? Because what he did was directly replace, in the order of his chain, his DIY overdrive/distortion that someone else had made for him with the fuzz I made. The DIY overdrive had no problems at that stage in the chain. What makes the fuzz different, the gain, or transistor configuration?

Thanks so much! We will try it at the first position and see how it goes...

[saison94]

Also, aren't all Boss pedals buffered? Why would the fuzz work after a DS-1 and MetalZone in my chain, but not after a TS and Chromatic Tuner in his chain?

[tiges_ tendres]

Also, aren't all Boss pedals buffered? Why would the fuzz work after a DS-1 and MetalZone in my chain, but not after a TS and Chromatic Tuner in his chain?

Because we think the Wah might causing your problems, not the other buffered pedals.  There are lots of topics on wah buffering and fuzzes if you search on here.

[CynicalMan]

The wah would only cause problems when it was on. The bypass for most wahs is a loaded but not buffered bypass, which means that the guitar's output impedance isn't affected and the fuzz's sound doesn't change. If the wah was a weird one that did have a buffered bypass, that would be a different story, but the buffered pedals are the main issue. Output buffers are added to wahs because wah into fuzz can sometimes cause oscillation. The buffer prevents this and the filtering from the wah hides ugliness from having a buffer before the fuzz.

Just wondering, is this symptom of buffering fuzz specific? Because what he did was directly replace, in the order of his chain, his DIY overdrive/distortion that someone else had made for him with the fuzz I made. The DIY overdrive had no problems at that stage in the chain. What makes the fuzz different, the gain, or transistor configuration?

It happens with fuzz, some transistor distortions, and some designs with a low input impedance. The fuzz has a very low input impedance, which also varies with the signal. This decreases the output of a pickup and it rolls off highs. When a buffer comes before a fuzz, this doesn't occur nearly as much, which results in an ugly, glitchy, and harsh sound.

Also, aren't all Boss pedals buffered? Why would the fuzz work after a DS-1 and MetalZone in my chain, but not after a TS and Chromatic Tuner in his chain?

Because you like that sound?  

[saison94]

Well, I certainly hope it's that simple, Cynical Man.

I haven't had a chance to check with my friend to see if placing the fuzz at the beginning of his chain made a difference. But as per your final comment, I know what it sounded like on his set-up, being placed after buffered pedals in the signal path. It sounded just as you described: glitchy, harsh, obnoxious. Especially with power chords, it just sounded overloaded.

However, when I took the same pedal home and tested it on my set up, with two Boss pedals preceding it in the signal path, it sounded just fine. So, yes, I DO KNOW what it's supposed to sound like!

So, again, if it's really the buffers that's causing the problem, why doesn't it have the same issue when I recreate a similar chain scenario on my set-up? I mean, I have Boss pedals that work just fine with it, so are some Boss pedals not buffered? Why did it play just fine when it passed through his Super Chorus but not his TS or Tuner? Are all the Boss pedal input buffers configured the same way, or do they each have different impedance? Would multiple buffered pedals create a cascade of impedance issues whereas one (i.e. his Super Chorus) would be less forgiving and allow normal sound/signal to pass through?

Sorry for all the questions, but if it's just something as simple as saying it's the buffers then my experience doesn't bare it out. Unless there is something I just don't know about different Boss pedals...

[ayayay!]

It's a typical 9v power supply

I've been watching this thread and can't help but think your friend might be exceeding the available mA in his power supply.

Try putting just one pedal in that chain on battery or another power supply altogether.  And make sure there are no dead batteries inside of those pedals.  

If I'm way off, I'm way off, but at least you'll know that is/isn't it. 

[saison94]

Thanks for the suggestion, but we basically tried that when I was over there. He has a Dunlop DC Brick, with multiple 9v outlets he's powering his entire board with. He didn't add the pedal I made to his chain, but rather replaced his old DIY overdrive with it, so I wouldn't think it would be exceeding anything. I brought over my One Spot and its daisy chain, as well as my standard Boss 9v wall wort, and it didn't make a difference.

Still haven't heard back from him, I think he's out of town. Sure hope it's only the buffers in his Chromatic Tuner and TS, but again, why would that be the case when it plays fine with my Boss peals?

[GibsonGM]

Other thoughts:
Try your pedals with his amp and the guitar that was being used during 'glitch time'. It might be something completely unthought-of.  See if you can reproduce your pedal chain thru his amp, his guitar, in other words.

Try removing pedals from his chain 1 at a time, and you might find out which one isn't playing nicely.   Alternately, hook up your fuzz, then start adding his pedals 1 at a time.

Try measuring for DC on the output of your fuzz (and the other boutique pedal he's got).  Someone might have messed up on an output cap (??).

AYAYAY!  could really be onto something there, over-drawing from the PS could cause the voltage to drop, mis-biasing the fuzz....yuck....check that.

PS - you probably need to do some actual voltage measurements here, and not just plug n play - you want to know what's happening inside the pedal, and to rule out your build, if possible...

[zombiwoof]

Thanks for the suggestion, but we basically tried that when I was over there. He has a Dunlop DC Brick, with multiple 9v outlets he's powering his entire board with. He didn't add the pedal I made to his chain, but rather replaced his old DIY overdrive with it, so I wouldn't think it would be exceeding anything. I brought over my One Spot and its daisy chain, as well as my standard Boss 9v wall wort, and it didn't make a difference.

Still haven't heard back from him, I think he's out of town. Sure hope it's only the buffers in his Chromatic Tuner and TS, but again, why would that be the case when it plays fine with my Boss peals?

So your saying the fuzz works fine by itself when the buffered pedals are in bypass mode, in your chain?.

Al

[saison94]

So your saying the fuzz works fine by itself when the buffered pedals are in bypass mode, in your chain?.

Al

Yes. And this is with the buffered pedals in front of the fuzz in the signal chain.

Gibson, thanks, I'll give those suggestions a run-through when I can. As for an output cap, the fuzz circuit I built is exactly as shown in the schematic I posted earlier, so it does have a 10mf output cap, at least that's what I take it as.

Could you explain a bit more about overdrawing from the power source and measuring DC on the output? I have a multi-meter, but I generally use it for testing continuity and transistor voltages. How do I use it to test DC on the ouput?

[jasperoosthoek]

Just a few anecdotes about this, hope it helps:
It sounds very similar to what happened when a friend wanted to demonstrate his new Morley Wah pedal. It has a so-called true-tone-bypass circuit. Not true bypass but just a buffer which is always on... Even though all my pedals run on completely separate power supplies the wah didn't work with my Ge Fuzz even when the wah was turned off (due to the no-bypass circuit). The sounds it produced were accurately described by your previous posts. Just as if it was starved of voltage. But, I think it is not the Fuzz which fails, it was the wah. Apparently it couldn't handle low input impedance of the fuzz (which it really should not have to handle IMO). I told my friend that I never wanted to see his wah in my house again .

Some years ago I built another fuzz face for yet another friend. He complained about the same thing. It didn't work after his Boss () distortion. The volume dropped immediately when he engaged the fuzz. I never really checked out why, the fuzz wasn't really his thing and he lost interest in the unit. Still, it's a common problem to me at least.

My crybaby clone wah works (fails) perfectly 'fine' with the fuzz: It's starts screaming as it is supposed to: The low input impedance of the fuzz breaks the signal chain in the wah, making it sound almost as if it is completely pressed down. As long as it doesn't oscillate it's fine to me. It does not wah anymore but what you get in return is very pleasing, at least to me. I can always use my Colorsound Tonebender if I want a conventional wah+fuzz sound (just like Tony Joe White). The TB has a normal high impedance input and works with anything.

My point is that conventional Fuzz circuits can be very tricky with other pedals due to their low input impedance. The best you can do is to try to add a buffer that sounds just as good as the pedal without the buffer. Or try to put it in front of the chain or any place that works.