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My take on the Distortion+ (Ehm, I can't see this post anymore)

Started by Max, July 23, 2020, 06:18:47 PM

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Max

OK, nothing fancy, classic distortion circuit from MXR. But.
I had a look at the mods proposed here and there, I tried some and decided I didn't like them.
Two of the mods (bass and compression) were very subtle (i.e. I couldn't hear the difference) so, I discarded them. And I didn't like the way the tone control was implemented: instead of a potentiometer in series to ground with the shaping cap before the volume pot, I replaced the 10k resistor at the op-amp output with a 10k potentiometer, and put a capacitor on the centre pin of the pot to ground. Actually, I put two caps, with an on-off-on switch, so I can have two settings or disable it entirely.
Then the diodes: since I'm dumb, I misunderstood the circuit, and the result is unexpected: I have an on-on switch that connects the diodes EITHER to the op-amp feedback (soft clipping) or to the output (hard clipping), but I can't have them together. Plus, and here comes another mistake, I ordered the wrong switch, an on-off-on instead of an on-on, so when it comes to switching diodes types I have three options:
- fully symmetric (parallel of 2 1N34 in series)
- "slightly" asymmetric (parallel of 2 1N34 and 2 BAT41)
- "very" asymmetric, that is, 2 1N34 in series to ground only.
The effect is very pronounced, also the tone control is much more effective. I think I tried a 741 and an LF351 as opamp, but I don't remember which one I left in, I suspect the 741.
Ah, yes, the graphic: I didn't really know what to do so I made this sort of faded grey&white which includes part of the schematic.
OK, enough talking (or writing... or reading? whatever) here's a couple of pictures (and the final schematic, maybe it's clearer than my attempt at explaining it)
Ah, there's a lot of space in the top of the enclosure because it's recycled from another project.
Enjoy!