[sdiy] mono/poly mod, electonic basics

[Moho Disco]

I second the motion for all the pros on here to answer thom's questions...
'cause I'd like to know too!

Lava

At 10:25 PM 11/19/2001 -0600, you wrote:
>Hello,
>
>I just modded my Mono/Poly to accept an external input to the filter. It 
>works, but I was wondering if you guys could tell me exactly why :) and 
>also if I should alter it to protect the synth and/or input.
>
>The filter uses an SSM2044. I used the datasheet, and at first thought of 
>adding the input straight to the first pin, w/ a preceding pot to keep the 
>signal down if needed. Lava at the Zen Mono/Poly site told me he had 
>already tried this, and it didn't work. Now, I figured it might work to 
>put it at the amp which sums the 4 vco signals, and it does. I thought it 
>would because I've seen it in so many schematics, but I don't really 
>understand it. Why would it work before the amp but not after? At either 
>place the signals are being jammed together, right? What makes that op-amp 
>a 'mixer', if that is what's happening?
>
>Also, I grounded the jack, but that's it. The mod is jack-->pot-->op-amp. 
>Is there anything I should do there for further protection? It almost 
>seems too simple and good to be true.
>
>Thanks for sharing the knowledge. I'm learning slowly, and I appreciate 
>all the wit and wisdom you guys share.
>
>thom
>
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