dumb buffer question

[pinkjimiphoton]

hey, does this thing actually work?
http://www.turretboard.org/?p=186




i built it a long time ago, and was messing with it last nite, cuz a friend asked for a buffer. since i'd built so many different buffers, i grabbed this out of the boneyard and tried it.

doesn't seem to DO much.

i checked my vero, it is 100% right to this layout... no idea where the actual schematic is.

but here's the thing.. it's WEIRD.

if i tie ground from the jacks together, it works... no ground connection to the battery or board needed!!

if i tie ground to a star ground, it won't work. if i tie it to the board, it will. weirder.

if i pull the dang chip (i used a 741) it STILL passes signal.

i'm stumped. i'd rather just box it up and be done with it, but i have a sneaking suspicion it don't DO anything..
can someone shine a little lite my way?

thanks guys!! may explain why this thing didn't matter as a wah buffer..

[Pyr0]

I don't know about that one Jimi, but I built Harald's Foxrock Wah buffer and it worked great for placing a wah in front of a fuzz.

[pinkjimiphoton]

hi al,
that's the same one i built, just a slightly different layout.
thanks tho, it clears up some of my questions!!
so this thing IS the foxrocks.
i didn't notice any real diff with this when i tried it.. wah before fuzz didn't really come to life like i expected.
but now i know what circuit it was... so thanks bro!!!

[slacker]

The top layout has at least a couple of mistakes that I can see. The bottom of the jumper that's connected to pin 3 of the opamp should be connected to pin 6. There should a jumper from pin 4 to ground.
I think it should work if you fix those. I don't think there's any real magic there though, it just has a bit of gain, possibly to match the wah volume and bypass? Then it has some resistance in series with the output to make the fuzz face play a bit nicer.

[Kesh]

Schematics. Like I can tell what's going on from a vero.

[slacker]

It's just a non inverting op stage with a gain of 2 and a 22k resistor in series with the output.

[pinkjimiphoton]

Schematics. Like I can tell what's going on from a vero.

quote myself: "i checked my vero, it is 100% right to this layout... no idea where the actual schematic is."

[pinkjimiphoton]

thanks ian.