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Project: Corvus (Op-Amp Big Muff)
Variant: The "Modified" Tone Control

Build description

RESISTORS: All 1% metal film. Carefully rechecking the values helped ‘coz a lot of those have out of range values. I’ll be using Yageo brand resistors from now on.

CAPACITORS: All Panasonic solid polymers and/or low ESR mini electros & premium quality film & stacked metallized caps.

DIODES: six (6) 1N914

I opted for the “Modified” tone control.

OpAmps: I conducted experiments with several OpAmp combinations & finally settled for an RC4558P for IC1 and NE5532 for IC3. This is the best OpAmp combination for me.

OTHER OpAmp combo tests I tried:
• 4558 on IC1 + 741 on IC3 = lacks headroom. I had to turn the volume knob all the way up to try to match my guitar’s clean volume.

• two (2) NE5532 = the overall sound lacked the punch

• two (2) 4558s = similar to just using one 4558. Just a little louder.

Just FYI. I use a P-touch 2730, Mac & Win compatible tape printer for the labels, 3M vinyl car wraps for color & aesthetics & ribbon cables for the pot connections. Last but not the least, Small Bear’s light plate!

TESTING EQUIPMENTS: Marshall JVM 205H head / Marshall 1960A cab / IBANEZ S5470Q guitar. Jackson Japan-made Warrior guitar with genuine SD Invader humbuckers. Only Corvus Fuzz is connected.

TEST RESULTS: With the Tone Bypass switch in the OFF position, the sound is unmistakably 100% Mosrite Fuzzrite, the fuzz pedal that the late Iron Butterfly guitar player Eric Brann used in the IAGDV and Ball albums. Amazingly, the Corvus sounds more Iron ButterFuzz-like compared to all the Mosrite fuzz clones I have. And of course, the overall sound & tone quality of the Corvus Fuzz mimics the signature guitar sound of the Smashing Pumpkins dead-on. With the switch in the “Modified” position, I have no doubt that this redesigned fuzz could very well rival other pedals in its kind when used into the hard rock & metal genre ‘coz it takes on another distortion character as soon as the toggle switch is engaged in the Modified position where the tone control is at your mercy.

Thanks to Kevin & the AION techies for a better (if not the best) re-design of the BMP OpAmp version.

How many BMP variants have you cloned? Try the Corvus Fuzz & enjoy the journey from psychedelia to metalmania. Tell us about it, please. Thanks.

Modifications or part substitutions

AION stock tone control mod