Gretsch Controfuzz Problem....

[jaguarcat311]

1. Gretsch Controfuzz
2. http://www.diystompboxes.com/pedals/schems/CONTROFZ.GIF
3/4. I modified a few things: instead of two 748 opamps, i used a tl082 dual opamp, the first .47uf cap is polarized, the second is nonpolarized. i am considering switching out the polarized cap, i just found another nonpolarized .47uf cap. i also added an extra 1n4001 clipping diode to one side of the clipping diode section to get asymetrical distortion. i am also considering getting rid of that extra diode too. I used a piece of cardboard to put everything on, poked holes through it and wired point to point. since i used a TL082, i had to use +/- 9 volts, two batteries.
6. Alright, this one's odd. i plug it in, works great..........then slowly fades out to nothing, at nothing i noticed it will make that terrible distorted sound when you hit the strings really hard......this is a new one to me.... works fine, fades to not working fine. while its working fine it has about the same output as my electra distortion pedal.
7. 9 volt batteries measure just over 6 volts each. fresh out of the package.....i made a mixer using the same IC with 2 9 volt batteries, out of the same package, the mixer works great and the batteries in the mixer measure the same.
on the IC, i used opamp A for the first opamp in the schematic, and B for the second opamp.
voltages are:
V+: starts at 6, gradually drops to 1.4
V-: starts at -6, gradually drops (rises?) to -.76
Non Inverting inputs A/B and Inverting inputs A/B: all measure 0
output A:.03
output B:.03

[RickL]

Did you build it exactly the same as the schematic except conecting pin 4 of the op amp to -9 volts instead of ground? If so it won't work.

The pedal has been designed to work with a single 9 volt battery and will work using a TL072 or any other dual op amp. The 100k/100k/220uF combination that connects to the non-inverting inputs of the op amps forms a voltage divider to give an artificial ground.

If you want to run the pedal on a dual supply you'll have to get rid of the voltage divider and connect the non-inverting inputs to ground.

[puretube]

[OT]: testing the replyfunction of jag`s thread...  :wink:

[EDIT]: seems to work OK for me...