calling Fp, and bill mergman...microsynth...

[swt]

Ok guys. I have the real unit from a friend. here are the corrections to that pdf schem. R8=33k. R12=1k5. R21=22k. R68=12k. R89=47k. There's a 10 resistor between R105, and connection 1 on the pcb, so that's lifting the earth at the output of ic 1 by 11k. R97 and pin 2 of ic 14 connects to ground. And Bill....yours maybe boosting signal when using the square wave, because there's a missing resistor. From pin 1 to gorund of ic 8, there's a 10k resistor, so that pot becomes the result of the paralell 10k and the 100k pot. Also...interesting, the fet is a bf245a, and it goes, source to V+, gate to pin 1 of ic 18, and drain to 12k resistor to V-. All diodes 1n4148. So this is it. The rest is correct. hope i can make it work now. I'll be in touch. Thanks!!

[Andy]

to sound like a newbie,  :shock: what does the microsynth do to your sound?

[Rodgre]

The E-H microsynth combines a lot of circuits for tone shaping. It gives you an octave below, an octave up, plus the straight signal, an attack delay that gives you an automatic volume swell and a cool sounding voltage controlled filter. You can expect everything from brassy and synthy fuzztones to silly sounding bleeps and bloops. It's a monophonic device, as far as the tone generators (octaves) are concerned.

Roger

[Bill Bergman]

Looking forward to the results and dreading doing the fixes. Let us know if the corrections make major improvements. Your endevor is very commendable.

[swt]

Another one....i took the trim pots out, and the squelch one is correct, it's a 100k pot. But the preamp gain is also a 100k pot, not a 10k as it's suppossed to be in that schem. By now, i have everything working as in the original, but the only problem i found is that on notes below the C on the 5th string, and 6th, i'm getting too much response on the vcf, and the attack delay, so i'll check for errors, on mine and recheck everything on the schem just in case. Keep in touch for updates.

[Rob Strand]

Anyone got a link to the PDF? I think I've got a .ps copy somewhere, not sure  if it's the same - I'd like to get the PDF if possible.

Good luck sorting out the schem and debugging.

[swt]

ok...the last one. It's all ok. in the first thread, the 10 means 10k. I've checked everything, and what i said it's ok. Mine works exactly as the real one. It even does all the crappy things in suboctave, etc, but it's really fun. The only difference i forgot to mention is in the power supply. I didn't use the original. I've measured the original and it's +8volts, -10volts from ground. So i used a 7808, and a 7910, in a different power supply, that works good. So...as Paul Perry told me...happy hacking.
Rob....send me an email, i'll send you the pdfs, correct the errors from this thread, and feel free to ask me anything you want to know.
sfeirwt@infovia.com.ar.

I have access to a qtron, and all the voodoolab pedals...so who knows what's next. Anyone interested?. Maybe shooting photos and colaborating with pcb tracing, etc?. Let me know. Have fun!

[Bill Bergman]

Well I made the corrections to mine that SWT uncovered and there seem to be a favorable improvement. Then, the low octave got weak....a wire came lose from the blend pot. Fixed it, plugged it in again and another pot that was dangling under the pcb shorted something out. Smoked R99 and overheated Q5. I replaced them, but Q5 still overheats. I don't think there is an external short. I'm afraid it another bad component somewhere. I can't trouble shoot it with a probe or I'll smoke Q5. Actually with I was able to probe some before changing some of the pot settings. Apparently one of the pots when set at what ever setting may cause Q5 to over heat.

This sucks, after laying of pedaling for awhile, I built a failed Woody and burnt out one of my favorite complicated pedals this weekend.

[JN]

Hi Stuart,

Sorry if you already said this, but could you say what PCB layout you used?

Thanks, and congrats on a great project.

Jake