roland double beat HELP!

[objectx]

Hi all, I've just finished off a roland double beat build based on this schematic, I'm just using the fuzz section:

www.elektroda.pl/cir/guitar/Roland%20Double%20Beat.pdf

Problem is, it's not working... I'm getting what sounds like a very nice fuzz but at an extremely low level. the tone, level (a 100k pot to ground which I added to the end of the circuit) and sustain controls sound like they're doing what they're meant to but the whole thing is just whisper quiet. Has anybody else had a crack at this circuit? I'm using 2n3904 in place of the 2sc1000 transistors.

[R.G.]

Have you read "Debugging Thread: What to do when it doesn't work." ?

[objectx]

ok, sorry looks like I got ahead of myself, I'll grab some voltages and post them: this is the layout I'm using (done in eagle), sorry if you can't see all the values (i'm just getting to grips with eagle):





forget the bad connection to ground at r12 on the layout, that is good on my etched version.

[objectx]

sorted this problem out (damn solder bridge), and I can confirm that this layout/schematic works (my layout is a bit rough around the edges) and sounds very similar to the original which I had got hold of from a friend for reference. Nice fuzz, although the sustain control doesn't do a whole lot.

[Dan N]

I don't know if it would make a difference, but I do have one with a 50KA for the sustain pot. Ha, and a 50KB for volume. Exact same fuzz pcb.

I think it may be a later model as it uses a Crybaby style gear instead of the mechanical whatchamacallit. It also has a different wah board.

[objectx]

Interesting hmmm, ok I might give it a shot with a higher value for the sustain pot. The schematic floating around that I based it on (see above link) doesn't show a volume pot at all (although the original does have one) so I used a 100k. I haven't compared pot values but the action of the sustain pot in the original is identical to my build.