Cornish-Style A/B/C Workalike

soulsonic · Post by **soulsonic** » 22 Aug 2007, 23:22

This came up over at Aron's forum and I whipped up this workalike real quick. It's based on the description of the original unit.
I'm not sure what the deal is with the differential outputs, but they're there like on the original if anyone has need for that.
I might do some kind of layout for it. I'm not real big on doing layouts though, so if anyone else does one that's fine with me.
Enjoy,
http://aronnelson.com/gallery/soulsonic ... _Style_ABC

soulsonic · Post by **soulsonic** » 23 Aug 2007, 04:04

Here's a basic design for a circuit board for it. Nothing very fancy. If anyone wants the original ExpressPCB file for it, I can provide it.
http://aronnelson.com/gallery/soulsonic ... _ABC_Board

analogguru · Post by **analogguru** » 23 Aug 2007, 04:37

If the original cornish design looks the same, he should be sent to the desert....

Please use a resistor of at least 560E (better 1k) in series with the output of the op-amp, it is really not necessary to shorten the output of the IC (with signal applied !) to mute the path (full load!).

analogguru

soulsonic · Post by **soulsonic** » 23 Aug 2007, 05:45

Yeah, that would probably be a good idea. I just whipped it up quickly this afternoon. Though, I have shorted the outputs directly before and it really hasn't caused a problem. The guitar signal is so weak that very little power is being dissipated when it's shorted. But of course with stronger signal... it might not be so forgiving.

But yes, I see a resistor would be a very good thing there..... sorry I wasn't seeing it correctly in my head what happens when the switch is shorted with a resistor there. I kept imagining the resistor being in parallel with the output in such a way that it would cause a voltage potential across the input of the following device and make it hum. But I can see now that it will not happen like that; the following device will have it's input shorted (which is the main thing we want here) and the opamp output will be going to a small resistor as a load.

Thank you very much for pointing that out! I will edit the schematic to reflect the correction. Sometimes I rush things and don't think correctly.

soulsonic · Post by **soulsonic** » 23 Aug 2007, 06:28

Okay, the schematic has been updated.
http://aronnelson.com/gallery/soulsonic ... _Style_ABC
I'm not going to bother changing anything with the board because it's intended to be a guide for hand-wiring it on perfboard not a press n' peel or anything like that.

analogguru · Post by **analogguru** » 23 Aug 2007, 06:39

The guitar signal is so weak that very little power is being dissipated when it's shorted. But of course with stronger signal... it might not be so forgiving.

You always have to keep in mind, that you are dealing with guitarists looking for "that ultimative sound" - so the worst-case scenario can be considered as "normal".

analogguru

DWBH · Post by **DWBH** » 26 Sep 2007, 19:23

all links are down.

dave_b · Post by **dave_b** » 26 Sep 2007, 20:01

DWBH wrote:all links are down.

Aron upgraded the gallery and old links are no longer valid. Here it is.