Earth Sound Research - Graphic Fuzz (Data Dump)

[FOXFIRE]

ok maybe i don't quite have the wiring right...

[jerms]

i don't understand it but i think this is it!

[jerms]

yeah this thing is ungodly loud!! i was using it on a fender champ earlier (so as to not wake the napping baby). and when i hit the switch to turn it off i couldn't hear the signal at all, since i had to turn the amp to under 1 to control the fuzz!! ef'in LOUD.
hey sickle or captain, on yours does the signal disappear when the filter is turned fully up?

[SonicVI]

I think the filter pot is just controlling the gain of the opamp, so it would make sense that when it's turned all the way one way that you would be turning the gain down to 0 (from 100 at the opposite extreme). Usually when this is done there will be a resistor in series with the pot to set a minimum gain that's above zero, but that's not done here.

[jerms]

where's the analogguru to explain all this!!

[SonicVI]

Yeah, on second though, I don't think an opamp can have zero gain, we need a smart builder.

[jerms]

i don't get how you get a moving filter with a pot and a .1 cap. i guess that's not all there is to it though. i wonder if the output is feeding back to the input through the filter pot?

[jerms]

the clone, sounds just like the original!! super easy build!! the original uses linear taper pots, audio pots let you have a little more control over the gain (ie.. doesn't get so loud so fast).

[FOXFIRE]

I drew up a schematic, would you mind having a look at it?

http://www.aronnelson.com/gallery/main. ... C.png.html

[jerms]

the only thing different i see is the ground on the output jack is connected to the bottom of the level pot thus connecting to the 220 ohm, pin 3 on the IC, the .1 cap on the input etc... the input jack grounds through the chassis. and there's an isolated switch on the input jack, that connects the - of the battery to pin 4 on the IC and the .1/10K. kinda strange... the - of the battery doesn't hook to the chassis & circuit ground...