# Backfeeder Mods & Ideas



## prairiestate (Jun 15, 2019)

There was a thread on this circuit on the old forum, so let's get it going again and make this a resource

First, I got the PCB with the mistake -
What is everyone's experience with a suitable replacement for the 2SC732?

Reducing clipping -
I believe lifting D5 and D6 works. You could place them on a toggle or not install them

LFO speed -
Anyone have any experience? I'm looking at IC7.1. R21 perhaps?


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## Chuck D. Bones (Jul 1, 2019)

The bottom path (Q2, IC7.2, IC8.2) is basically a DS-1.  Taking out D5 & D6 will definitely reduce the clipping, but Q2 is easily overdriven and can contribute a fair amount of distortion.  If you want a real clean path, you need to also change R29 & R30 (a common DS-1 mod).  Try the diodes first and see if that's good enough.

What do you want to do with the LFO?  Go faster or slower?  By how much?  The LFO freq is proportional to 1 / (R21 * (C14 + C15)).  I would not go much higher with R21, because R25 and C18 are loading the LFO timing circuit.  If R21 gets too big, the LFO will not operate correctly.  You can make C14 & C15 bigger or smaller.


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## Ariosto (Jul 9, 2019)

Did you already made the mods? Are the results satisfying?


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