Chuck D. Bones
Circuit Wizard
What a pedal! So many knobs and switches! Michael Ibrahim took the Crunch Box, already a great distortion pedal, to a whole 'nother level. I built this one per the Build Docs except I subbed 47pF for the two 56pF caps and NOS Fairchild FD100 diodes for the 1N4148s. Would have worked right out of the gate had I remembered to install LM833s in the sockets. 
Bench testing was going pretty well until I checked the -9V and +18V rails. They were more like -6.5V and +14.5V. I had used a NOS 39Ω carbon comp resistor for R100. Turned out to be more like 55Ω. In this case NOS meant Nasty Old Shit. Not too surprising that a 40+ year old CC resistor would drifted that far out of spec. Gotta remember to test those NOS parts before installing. Even 39Ω seems a bit high given how much current this thing draws. I popped in a 15Ω carbon film and we were off to the races. The 2nd stage hits the LED clippers pretty hard and they glow brightly when the GAIN is turned up. Might be fun to mount them on the other side of the board and drill holes for 'em in the front panel for a little "magic eye" action.
Huge gain range, tons of volume and those tone controls! Best 3-knob active EQ I've heard in a pedal. With the CLIPPING switch in the middle and the GAIN rolled back, it's a clean EQ/boost capable of 10Vp-p output. Or bump up the GAIN for some saturated opamp distortion. With the CLIPPING switch set to LEDs, it has a nice fat, dynamic tone. The Silicon CLIPPING setting is more compressed and a bit brighter.
This pedal plays nice with humbuckers or single coil pickups. Highly recommended. Check out the User's Manual on the MI Audio website.
I started with a predrilled 6-knob box from Tayda, enlarged the LED hole and drilled the two switch holes.
That board is a snug fit in a 125B case. Didn't need a stereo output jack, but that's all I had.
Bench testing was going pretty well until I checked the -9V and +18V rails. They were more like -6.5V and +14.5V. I had used a NOS 39Ω carbon comp resistor for R100. Turned out to be more like 55Ω. In this case NOS meant Nasty Old Shit. Not too surprising that a 40+ year old CC resistor would drifted that far out of spec. Gotta remember to test those NOS parts before installing. Even 39Ω seems a bit high given how much current this thing draws. I popped in a 15Ω carbon film and we were off to the races. The 2nd stage hits the LED clippers pretty hard and they glow brightly when the GAIN is turned up. Might be fun to mount them on the other side of the board and drill holes for 'em in the front panel for a little "magic eye" action.Huge gain range, tons of volume and those tone controls! Best 3-knob active EQ I've heard in a pedal. With the CLIPPING switch in the middle and the GAIN rolled back, it's a clean EQ/boost capable of 10Vp-p output. Or bump up the GAIN for some saturated opamp distortion. With the CLIPPING switch set to LEDs, it has a nice fat, dynamic tone. The Silicon CLIPPING setting is more compressed and a bit brighter.
This pedal plays nice with humbuckers or single coil pickups. Highly recommended. Check out the User's Manual on the MI Audio website.
I started with a predrilled 6-knob box from Tayda, enlarged the LED hole and drilled the two switch holes.
That board is a snug fit in a 125B case. Didn't need a stereo output jack, but that's all I had.
