V3205 Dirtbag help please

[octa805]

Howdy,

Broke cardinal rule #1 by not rocking it before boxing it. I think this will be the final straw as far as me making excuses for not creating a test rig.

That said, here we go and may bean forgive my stupidity.

(1) Project Name--Dirtbag v3205
(2) General description of the problem--Bypass works. Indicator LED works. No output when effect is engaged.
(3) Steps that you have taken to try to resolve the issue--Twisted knobs every which direction. Used audio probe to try and find some signal. Found some good signal but having difficulty figuring out where it stops.

IC 1-signal
IC 2-signal
IC 3-NO signal
IC 4-signal
IC 5-no signal. weird whining noise? Almost sounds like oscillation?
IC 6-signal
IC 7-NO signal. clock ticking? Just goes "tick tick tick tick"
IC 8-NO signal
IC 9-NO signal

I've also tried prayer.

(4) List any substitutions you used for parts/values-all the V3205 revisions per the updated build doc

Here's a couple pics that may or may not be helpful.




Willing to do whatever. Just could use some direction. Thanks!

[madbean]

No signal to pin7 of IC4 (the first BBD)?

[octa805]

howdy.

If I'm getting the pinout correctly I believe I am only getting signal at IC 4 on pin 13?

It's the 2nd pin from right directly above bias 2 trimpot.

get a little feedback/whine from what I think is pin 7 on IC 4.

thanks

[madbean]

It's pin13 on a 14 pin package, but I call it pin7 on the schematic since there are only 8 pins total for the IC. Anyway, that's signal in.

So, what should happen is the delayed signal out on pins 3 and 4 (or 6 and 7 if you prefer) but the BIAS trimmer has to be set correctly for that output to occur. Do you get any audio out of those pins in any turn of the BIAS1 pot?

[octa805]

just pushed bias 1 around and found a spot where it gives signal forward

did the same for bias 2 and got the 2nd BBD to pass

plugged it into the amp and got some signal

nice!

delay doesn't seem to be really doing a ton. guess I need to figure out how to bias it now but at least I got something to work with. thank you so much!

also, does the D1 LED need a CLR or is it built into the board? I don't have one & it's not lighting up.

thanks!

[octa805]

Not getting as much delay as expected

This normal for the 3205?

Side by side with my carbon copy and memory boy it sounds great but not as deep

Likely my poor biasing too

[madbean]

Follow the procedure outlined in the doc. You should get about 500-550 ms of delay. It's a matter of adjusting the bias and gain trimmers to get a strong signal through there.

D1 does not need a CLR. As you turn the Level pot up the signal will start to break up and light up the LED. If is still not lighting, please make sure you have installed it in the correct way and used a 2n5087 or similar PNP transistor for Q1.

[octa805]

as usual, you were totally right.

the delay times get great with more fiddling.

LED still eluding me but I'll figure that out

thank you very much. your projects are amazing and that a ding-dong like me can make something this complex is a real testament to the ease of use of your layouts and instructions. thanks again Sir Bean