Here are some samples. The first file is the yamaha thr on its own for reference (usb out). The difference between the other two is the feedback resistor in the first stage. The second gain stage isnt included yet. The tonestack pots are somewhere vaguely pleasing. Guitar is a strat bridge pickup
I think I'm reasonably happy with it at lower gain but at higher gain there's this fizzy distortion on top. I think that may be the op amp distorting (based on some Spice sims) so I'm thinking about putting a unity buffer in front of some other clipping diodes in the front as a boosted/hotter signal is going to make it worse. Not sure yet though. Maybe some filtering would be better but I think I'm struggling with no headroom and then the OP07 isn't rail to rail to make things worse.
It's also unclear how much the Yamaha is helping. Still waiting for the 8302 board.
Yamaha
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200k
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500k
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I think I'm reasonably happy with it at lower gain but at higher gain there's this fizzy distortion on top. I think that may be the op amp distorting (based on some Spice sims) so I'm thinking about putting a unity buffer in front of some other clipping diodes in the front as a boosted/hotter signal is going to make it worse. Not sure yet though. Maybe some filtering would be better but I think I'm struggling with no headroom and then the OP07 isn't rail to rail to make things worse.
It's also unclear how much the Yamaha is helping. Still waiting for the 8302 board.
Yamaha
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200k
You cannot view this attachment.
500k
You cannot view this attachment.