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Another pedal from my brother's garage. I vaguely recall my roomie Richard owning this back in the mid 70's. I modded it for him by adding a DEPTH knob. He later sold it to me, I loaned it to my brother and forgot about it. Until a couple of weeks ago when he brought it back. Back in the...

I built this in 1976 or 1977. It's basically an Electric Mistress with two more knobs. My brother found this in his garage. It's period-correct Electric Mistress right down to the Reticon SAD1024A BBD. Check the date code. Chips are (L-R): RCA CA339 quad comparator National Semi...

This was built in 1977 in The Valley (Oh my Gawd!). Looks to be all original. Board was wave soldered and there are no signs of repair or modifications. Battery power only. Not true bypass. No reverse voltage protection diode, although the circuit itself is pretty-much immune. No power supply...

Phill in Perth sent me a link to the Box of Germanium layout. It's basically a Zvex Box of Rocks with the MOSFETs replaced by low-leakage Ge transistors. A clever idea. I wasn't happy with the biasing and a few other things, so took the basic idea and ran with it. This is the current...

I bought a RAT 2 from Musician's Friend for $88. These days, RATs contain an OP-07 and are made in China. Just peeking in thru the battery door, the build quality looks ok. No premium parts. Cheap Chinese metal film resistors (the ones Tayda sells are much better). Aluminum electrolytic...

as used by Rock Icon David Bowie

I built this custom Rat for a client. Fine-tuned per his requirements. The sparkle gold paint looks so much better in person.

I've been meaning to breadboard this one for a long time. Not a bad sounding pedal, but there is a shit-ton of useless parts. Here's the PPCB schematic: The first useless part that jumps out is IC1.2. Why install a dual opamp only to abandon 1/2 of it? The CA3240 is a dual version of the...

I have been working on three Proco Rat pedals for a client. Also did some breadboarding. I have observed that the tone of a Rat is strongly dependent on the particular LM308 installed. These are all legit parts, but there is enough part-to-part variation to make a noticeable difference. Has...

This pedal gets pretty damned close to the real tone IMHO. The power consumption is low enough that you could install it in a Tele and power it with a battery. I breadboarded it per the Build Docs, except I used MPS6530 transistors (HFE around 70) and left out the switch. I installed 22nF for...

This started out as a request for a Rat with more gain and less midrange. I stuck a booster-limiter in front of the Rat, with a BASS cut at the input to the booster and and a MID cut at the output of the booster. The booster provides up to 40dB gain. D1 & D2 keep U1B from saturating at high...

A client asked me if I'd ever heard the Roland GP8's phase shifter section. I hadn't, but I found a schematic and breadboarded one. It bears some similarity to the MXR Phase 100 in that it contains both variable and fixed phase shift stages. The Phase 100 uses LDRs and has 10 stages; the GP8...

I got a hold of one of these and had to trace it. It's a modified Silicon Fuzz Face, hand-crafted in the Czech Republic by Electronic Orange. Beautiful construction in a bullet-proof steel case. In the SINGLES position, C2 and the PU trim pot are bypassed. In the HBS position C2 & PU trim...

Here's the C3-PO parametric filter. Top view: 16 cuts 8 links, 4 on the bottom. For the bottom links, just bend over a lead to join 2 adjacent strips on the solder side. For example, the purple GND strips on the left.

This Vero layout is for the R2-D2 Opto-Face. Yeah, it is some Crazy Shit. Top View: 10 cuts 4 links - 2 on the top, two on the bottom. Bend D1-A over to join the two GND strips and bend the right-hand lead of R3 or R4 over to join the two pink power rail strips.

Back when I was a young lad, my friend & roommate Richard bought a Black Finger. As per usual, I would cajole him into letting me take it apart & trace the circuit with the the promise that he'd get it back intact. A very interesting circuit indeed. Years later he sold it to me and I still...

Another OD inspired by HamishR down under in Perth. His earlier versions had four JFETs and a different tone stack. I took one of the later versions, deleted a source-follower stage between the clipping diodes and FMV tone stack, fiddled with the EQ and clipping a bit and here's where I ended...

This pedal has received some rave reviews in the Build Reports forum, so I had to breadboard it and see what it was all about. The circuit starts out simple, with the first two stages looking pretty similar to the BluesBreaker. After that, there is a whole lotta EQ. At low GAIN settings, all...

Found this on PCBWay, designed by Glory to Ukraine. Based on the name, I half expected this to be a banjo pedal. This schematic is from the build docs. Most of it makes sense, although I fail to see the need for input and output buffers. I breadboarded it per the schematic, minus the input...

Guitar PCB offered this PCB as a bonus during a recent promotion. It's an interesting all-opamp version of the traditional BMP architecture. Note the diode soft-clipping on three stages, instead of the usual two. The gain is throttled in the 1st stage feedback loop, instead of between stages...