Weirdest thing ever! Help Needed Please! :(

[Ofek Deitch]

Hi everybody!

Well, I finally finished my first build, which is a "Vintage Fuzz" (based on the Axis Fuzz from FuzzCentral and with a few mods I made.. ). I think it took me about three or four months to finally finish this project, but it turned out super awesome, with the swirl painting and everything!

The problem is that when I put my modded Crybaby GCB-95 in front of it and play with them both on at the same time, while the Fuzz knob (of my Fuzz, of course..) is turned all the way up, I get this horrible screaming sound when the wah's rocker isn't all the way up (toes pushing down\ front side of the rocker is next to the ON\OFF switch... )

This happens only when the Fuzz knob is turned all the way up, or close to that, and when the Pre-Gain knob isn't turned down to midnight or so.. (The Pre-Gain knob is knob that's replacing the need to adjust the volume knob on your guitar every time you wanna use your fuzz.)
But when the fuzz knob isn't turned all the way up, the wah actually sounds pretty good though...

I have no clue why this happens and it's REALLY annoying so please help me if this has happened to you before, or if you know how to fix this problem !



Thanks a lot !!
Ofek 

[Seljer]

This is a know issue

The solution is to put a simple buffer in between the wah wah and the fuzz pedal. Typically people prefer to put it in at the end of the wah wah pedal so its only active when you turn on the wah, but you can put it at the start of the fuzz pedal too (this however noticebaly changes how the fuzz reacts to the guitar's volume knob).

Any type will do, either one built with an NPN transistor, a JFET transistor or even an opamp. Heres a simple setup with a jfet http://www.muzique.com/news/wah-pedal-buffer/

[Ofek Deitch]

Ok, so I tried FuzzCentral's output buffer, and now the screaming noise has stopped. The wah also sounds better with the buffer, but it lost a bit of its volume. 
What do you think caused that?

Is it possible to play with the values of the buffer in order to get a louder signal? Or maybe to put a boost or something in front of the buffer, or something like that...?

Thanks again!
Ofek 

[rockhorst]

The slight loss in volume is also a known 'issue'. It's inherent to a buffer that uses a transistor for the job, they have a gain of a little under unity. Two options:

1. Use an opamp to buffer the signal (has unity gain)
2. Build the buffer into your pedal and don't think about it. If you don't know it's there, you won't care. Or use a booster to bring the signal back up, but then again, it's easier to do that with an opamp too. Google for the AMZ booster/buffer boards.

[Ofek Deitch]

The AMZ Booster sounds like a great idea!
Although I'm not sure what diode is required - a 9.1V Zener diode is requested but the schematic does not tell me the exact diode I need.

Will this diode do the job?
http://www.ebay.com/itm/10-pcs-1N4739A-1N4739-VISHAY-Zener-Diode-9-1V-1W-Free-Shipping-/180841460312?pt=LH_DefaultDomain_0&hash=item2a1afdb258#ht_836wt_906


Thanks again!

[pinkjimiphoton]

or just wire in a 50k pot between the output of the wah and the switch...then you can dial in just enough resistance to make it work, without the buffer...kind of a passive buffer, seems to work better for me than any of the buffer circuits i tried.

[DekkerFuzz]

the output wire is purple in a crybaby right? what difference if i put the volume on the input or green wire? also will this mod take me above unity gain as well as below? anyone?

[pinkjimiphoton]

i forget which wire is which, use your meter and beep it out.
any time you add a pot, you'll lose a little volume, not gain it. depends on how loud the initial circuit is as to whether it's a problem.

go to geofex.com and look up the technology of the wah. rg will show ya all you need to know.

[DekkerFuzz]

thanks for the help, so i put a pot on the output purple wire, unfortunately i did not get the desired effect, when i turn it down in hope to put an end to the fuzzface occilation problem, it has to go quite low before i get rid of the squeal, but by then ive lost so much of my sound its unusable,  >:(and was actually surprised to find that this also lowers the volume when bypassed with the same effect as turning down your guitar, completely losing my tone . not the solution i was looking for but it may be handy for some other reason to have an overall volume control. so im goin to do what i thought i should have done originally and replace the 68k input resistor so i can set the volume of the wah circuit seperately, see if that solves it. how did roger mayer sort this?

[Ofek Deitch]

I found this (link below) a while ago but haven't tried it yet... sounds like a good direction.
http://tagboardeffects.blogspot.co.il/2013/01/foxrox-wah-retrofit-fwr.html

Give it a try a tell us how it turned out !