Bagel - a soft but lightly toasted boost/buffer

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earthtonesaudio
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Post by earthtonesaudio »

This is the most recent refinement of a generic boost/buffer circuit I've been using for a while. It's a soft clipping boost with a subtle crunch, like a perfectly toasted bagel. Bypass scheme inspired by Valve Wizard, diodes-to-ground soft clipping inspired by Thunderbird (and discussed in this thread).
  • I used a 10k linear pot but a different taper (log or audio I suppose) would let you omit R6.
  • My schematic says "opamp_quad" but feel free to ignore that and use a TL071 or similar.
  • D5/D6 LEDs are 2.5v high-efficiency types, and they're just to prevent opamp saturation with large signals. They do light up when I crank the gain and play loud with single coils, but I don't think they contribute much to the sound.
  • All non-LED diodes are 1n4148.
  • simulation: https://tinyurl.com/2avb3xqb
The clipping section on the output still allows a decent amount of voltage through at a reasonable output impedance, so it can still overdrive something later in the signal chain (like an amp).
bagel.png
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