Chuck D. Bones
Circuit Wizard
Ok, I'll admit that it needs a better name.
HamishR & I were playing around with the Marshall ShredMaster, trying to make it into something a little different. You'd think that a pedal with "shred" it its name would be a high-gain pedal. Not the case with the ShredMaster. For us, the best part of the GAIN setting range is at or below where the opamps start to saturate. So that's where we focused our attention. Stripping out one of the opamps up front was a no-brainer. Next, we tackled the tone stack. I started out with a stock ShredMaster on the breadboard and I could not find tone knob settings that I liked. So I chucked (pun intended) the SM's tone stack and started over. Here's where I ended up. It's 90% there, sounding really good with Humbuckers. I have one more tweak I want to try.
Knobs (L-R): LEVEL - BASS - MID - TREBLE - GAIN
Basically, it's not much more than a Distortion+ with a 3-knob EQ. This circuit provides a smooth edge-of-breakup tone. Chords ring clear; you can hear every string. All of the tone knobs work independently, very little interaction. TREBLE & MID are cut only. BASS is boost only. The flat setting is TREBLE = 10, MID = 10. BASS = 0. The Mid Cut is centered at 500Hz. The Bass Boost can recover some or all of the bass lost in the first stage. I skewed Vref a bit so that U1B will clip more-or-less symmetrically. Last thing I did was add R7. R7 causes mild asymmetric clipping in the diodes at moderate signal levels and really improves the tone IMHO. R7 is a 1K trimpot on the breadboard (not shown in the pic above). I have it dimed and it sounds great. The only thing left to do is try it with my Tele and see if it needs a FAT switch.
HamishR & I were playing around with the Marshall ShredMaster, trying to make it into something a little different. You'd think that a pedal with "shred" it its name would be a high-gain pedal. Not the case with the ShredMaster. For us, the best part of the GAIN setting range is at or below where the opamps start to saturate. So that's where we focused our attention. Stripping out one of the opamps up front was a no-brainer. Next, we tackled the tone stack. I started out with a stock ShredMaster on the breadboard and I could not find tone knob settings that I liked. So I chucked (pun intended) the SM's tone stack and started over. Here's where I ended up. It's 90% there, sounding really good with Humbuckers. I have one more tweak I want to try.
Knobs (L-R): LEVEL - BASS - MID - TREBLE - GAIN
Basically, it's not much more than a Distortion+ with a 3-knob EQ. This circuit provides a smooth edge-of-breakup tone. Chords ring clear; you can hear every string. All of the tone knobs work independently, very little interaction. TREBLE & MID are cut only. BASS is boost only. The flat setting is TREBLE = 10, MID = 10. BASS = 0. The Mid Cut is centered at 500Hz. The Bass Boost can recover some or all of the bass lost in the first stage. I skewed Vref a bit so that U1B will clip more-or-less symmetrically. Last thing I did was add R7. R7 causes mild asymmetric clipping in the diodes at moderate signal levels and really improves the tone IMHO. R7 is a 1K trimpot on the breadboard (not shown in the pic above). I have it dimed and it sounds great. The only thing left to do is try it with my Tele and see if it needs a FAT switch.
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