Guyatone PS-021

[Alex]

There's a schematic now available here: https://aionelectronics.com/schem/guyatone_ps-021.png
I want to draw a layout but I'm not 100% sure which components you'll need to eliminate to completely get rid of the flip flop switching system.
I was thinking: Q9, Q10, Q11, R15, R16, R20, R41, R69 and C10.
Any help would be appreciated.

[rocket88]

I think Q1, Q2, Q8, Q11, and their attached caps & resistors.

[Alex]

Cool Zach!
Would you remove the Input buffer too?
Is this what you've meant?

[rocket88]

Yea. That looks like what I was thinking. Isn't the input buffer removed in the schematic you just posted?

[Alex]

It is.

[aion]

The output buffer is safe to remove, but I would probably not remove the input buffer. I've never seen a Ross/Dyna circuit without it, and I'd be a little wary of connecting the CA3080 directly to the inputs.
A BJT input buffer is very resilient, but a CA3080 can be fried very easily by static and the like.

[Sergio]

Hallo aion, your pcbs will be using lm13700 instead? Easier to get. Thank you!

[GrooveChampion]

Theres a conversion daughterboard for that

[reddesert]

The CA3080 is well out of production and fake ones are such a problem that I think people should design for LM13700 in future. I understand the desire to keep vero layout size down, but for PCBs, designing for CA3080 is designing in obsolescence. Using a daughterboard works but then you're not keeping the size down anymore.

[Alex]

Added the input buffer back and an LM13700 version.

[reddesert]

Cool!  I really appreciate how responsive you and the other designers on this blog are to suggestions.

[R O Tiree]

Hi, aion,

If you have an original schem to hand, I'd really like to see the flip-flop switching system. I get Q10/Q11 switching between "dry" and "wet" for the output buffer, but I can't see what Q9 brings to the party. Was this pedal an all-or-nothing system? In other words, when you switched it on, you got both the Dynacomp and the exciter? Or could you get Dynacomp on its own, Exciter on its own or both together?  If it's the latter case, then I can't see how the "dry" signal gets to the exciter on its own, or how the "wet" signal gets from the output of the Dynacomp to the output buffer on its own.

Thanks.