Fuzz Face & CryBaby Wah... woes

[Triffid]

I don't think this is your normal FF, Wah problem.  

I built a silicon transistor npn fuzz face and it sounds awesome.. to me anyway.  The problem is that whn I put my Wah in front of it I get a very clean sqeal out of my amp, the pitch of the squel changes when I move the wah up and down.  The wah works fine by itself, my ff works fine by itself, and the wah works fine in front of my fulltone '69.... I add a grounded 1M resistor in front of the 2.2uf input cap... that didn't help...

Anyone ever seen this before?

Thanks in advance

[RDV]

Very common. Try this.http://runoffgroove.com/wahmods.html
Towards the bottom of the page is a cool buffer that will probably help.

Regards

RDV

[Oliver]

Very common. Try this.http://runoffgroove.com/wahmods.html
Towards the bottom of the page is a cool buffer that will probably help.

Regards

RDV

Hi once more from me :-)

does every Buffer work similar?
I build a TransistorBuffer (with a BC549C) and this made the Fuzz
after the Buffer sound fizzy, noisy and not liek the Fuzz i know..

Today i connected my Colorsound Overdrive After my Wah, with
Gain to low setting and Bass a bit up.
The Sound comes very close to that Hendrix number (VoodooChild SlightReturn) - the Intro.

Does the Fuzz Sound nealry the same after the Buffer from Runoffgroove, like for itself?

Thanx for your Hints

bye
Oliver

[Triffid]

Ya, I have seen that but I wasn't sure that would fix my current problem.  I thought that maybe I could do something simple on the  fuzz face side, since my '69 doesn't have this problem.  Then again it has germanium trannys with much, much less gain then my silicon version.   I am using BC108 (Q1 = 231, Q2 = 312).   Well... I was planning on doing that mod anyway.. hopefully it will fix this

Thanks

[RDV]

You both could try the input trimmer like the 69' has. I believe the way to do it is in the Boutique Fuzzface project at General Guitar Gadgets. As for buffers I believe the Mosfet one(@ Runoff Groove) is the best one for this purpose.

Good Luck & Regards

RDV

P.S.  Aron's 'Rocket' fuzz doesn't have this problem.

[brett]

This oscillation is related to the high gain in your Si fuzzface.  The simplest thing to do is reduce the gain.  Have a look at the thread on piggybacking transistors for low gain.  I'm sure that you could take the gain a lot lower without ruining you sound.  Add extra (duplicate) transistors in both Q1 and Q2 positions (connecting base to base and emitter to emmiter) (leave the collectors unconnected).  If the gain is now too low, you can raise it by putting a resistor bwteen the duplicate emitters.  Between 1k (lower gain) and 10k (higher gain) usually does the trick.  The "Miss Piggy" layout in the piggybacking thread makes this clearer.

Good luck.

[Triffid]

Thanks for the help... So why does this only show up when I connect the wah?  Without the wah I love the sound it puts out.

[Oliver]

Hi,

thats taceable..
as i turned the Gain of my FuzzFace down the WahEffect comes trough a bit more, than Gain turned up.

Another experiment i did was to set the Fuzz at lowest Gain and drive it
with my Tubescreamer. So the TS can be left with my favorite settings on it. But the fuzzsound is thinned out a bit more.

I will try the Runoffgroove Buffer - perhaps i have to "re-tweak" my Fuzz too.
I want to take care, that the Fuzzsound keeps the near the same, so that the activation of the Wah dont alter the Fuzz too much.

*now going to order the parts for the Buffer*

bye
Oliver

[Tobias Karlsson]

I don't think this is your normal FF, Wah problem.  

The problem is that whn I put my Wah in front of it I get a very clean sqeal out of my amp, the pitch of the squel changes when I move the wah up and down.  Anyone ever seen this before?

Thanks in advance

I don't think that you made this mistake, but when you connect the wha backwards, connecting the guitar to the output of the wha and the input of the wha goes to the input of the fuzz, you get this squeel that you can control with the rocker of the wha, raising and lowering the pitch of it.

It's weird sounding but fun for about one minute :-)

Tobias Karlsson in Sweden

[Triffid]

Thanks for the tip, but I am pretty sure that isn't what is going on here.  I can still hear my ill fated attempts at guitar playing through the squeel.  In fact, the squeel goes away while I am playing, then comes back as the notes fizzle out... weird sound.

I will try the output buffer on my wah and post how that goes.

Thanks very much for everyones help here

[gez]

I can still hear my ill fated attempts at guitar playing through the squeel.  In fact, the squeel goes away while I am playing, then comes back as the notes fizzle out... weird sound.

I will try the output buffer on my wah and post how that goes.

With any high gain circuit (overdrives for example) there’s always the possibility of feedback reaching the input.  Sometimes that feedback is positive and causes oscillation.

Just guessing here, but the wah is boosting frequencies in a reasonably narrow band as it sweeps, so at the end of its sweep the frequencies it’s accentuating (higher end of the spectrum) are probably the very ones that are close to the point of creating positive feedback in the FF when set to high gain.  This is why you’re getting whistling.

The buffer at runoff is designed to have unity gain and a reasonably high output impedance, which in turn is loaded by a FF’s low input impedance, so the wah doesn’t end up overdriving the overdrive if you catch my drift.  The wah should still retain its sound as there is no connection between the buffers input and output so any loading by the FF won’t affect it, it just attenuates the signal somewhat.

The source resistor and drain resistor can be tweaked to suit your set-up, just keep them the same value and re-bias with the trimpot accordingly.  Higher values result in more loading of the output (perhaps more suitable to high output humbuckers) and lower values create less of a loading effect (probably suited to weaker/single coil pickups).  The 10k value is a good  â€˜halfway house’.

I suggested this circuit to a fellow forum member who latter contacted me and said that it works well.  Brian also tried it and seems to like it too.  I haven’t tried it as I disassembled my wha sometime in the mid-nineties and still haven’t got round to reassembling it (the shame!), but it makes sense to me so it should (hopefully) sort out your problem.  

Thanks to Brian for sticking it on the net by the way!

[Doug H]

Oops! I just realized I'm in the wrong thread!

Doug

[Gearbuilder]

Hi,
If you put a buffer before your FF you're going to be near a Tone-Bender type of sound.Perhaps the tone-bender was built to allow to put a fuzz after the wha ?!
The squeal  disappears when you charge the wha's output with a circuit more adapted to the iotput impedence of the Wha
Bruno

[Triffid]

So is there a way to raise the input impedance of the ff without adversly effecting its sound?

[RDV]

So is there a way to raise the input impedance of the ff without adversly effecting its sound?

The Fulltone 69' does it with a 50K trimpot in line with the input that he labels 'bias'. You can do this also, it will allow you to preset a certain amount of volume cut which should allow you to use your fuzz and wah together.

Regards

RDV

[Gearbuilder]

Hi,
For my part no.At each time you put a component in the signal path,you are going to change the sound.The good question is; what can i do for less changing the sound?
You have to try them then use the best you like.First :passive solution Try a 50k pot this lower the sigal (the current) but this affects  the sound a little (bandwith are affected too)but it works well with wha.(i thing that Prescription do in his FF)
Second solution ;active .input buffer;the goal is to have the most transparent buffer,try with fet or BC at unity gain.Put a switch to allow ear with or without(A/B testing)
Third  :put an effect beetween the wha and the FF.If our idol FF were not
input modified ,they didn't have the sqealing problem by put another effet;univibe(it's not a true bypass)or octavia or other stomps
I've read a lot on this on the web
Well, try again
Regards
Bruno

[Triffid]

I had a 40k trim pot laying around so I tried that instead of the 50K, worked like a charm.  That darn squeel is no more.  To tell you the truth, the effect was not altered too much, and if it was I think it was for the better.  Before it was a ridiculously over the top fuzz, now it is just over the top

thanks very much for everyones help...

A little off topic...

My silicon fuzz sounds kinda jangly/metallic when I turn my guitar volume down to around 5... it isn't a really bad sound, just a little unusual... has anyone else had this type of sound with a silicon fuzz?

Thanks again

[petemoore]

I think every one of my various FF builds has had a different characteristic sound to the Guitar Volume Rolloff...

[Gearbuilder]

Hi,
i'm happy for you,it's ok now for the fuzz,but what do you mean by jangly :metalic ?If it's a little buzz following the note ,this may come from the parasitic capacitor of your trannys.I try several silicon's: BC 108,BC109 ,some with metal can or plastic :some have much buzzy harmonics than others .This harmonics often could be too big then you ear them if you roll down and you get again too much gain.You can add a capacitor beetween the base and the collector (see fuzz-central or Jimi Hendrix Fuzz-Face by Jim Dunlop)this cuts the high-ends but smooths often too much the sound.
The best solution is to try low gain transistors.It's difficult to find BC109 with less than 120Hfe,they are often much than 200Hfe.Find them in old radio's ,they are not so changing with time like the germaniums. :wink:
Regards

Bruno

[Gearbuilder]

Hi,
ooops twice post!