Another typo: The transistors being used as input and output buffers are labeled as BC558 transistors when those are PNP transistors instead of the NPN transistors that the schematic shows. Overall, quite a nice and neat design. Good idea to use a 555 timer for a switch mode power supply. I've done ...

I find it remarkable that despite how many people claim to hate the Metal Zone, there are so many pedals out there that are very similar to it. Off the top of my head, I can think of these: EHX Metal Muff (identical to a Metal Zone except for having a locked-out mid frequency and a practically usele...

Yeah, I think we'd love that. More knowledge is never a bad thing.

I'd say it looks very much like Adrian Emsley's work. The choice of op amps, the rows of resistors, et cetera.

Yeah, there are some differences between my schematic and the uterror schematic. I'm not sure if the uterror schematic is supposed to be an accurate tracing of a real Micro Terror or if it is supposed to be a design for building your own Micro Terror. Either way, there are some errors with the uterr...

Okay, so this is what I've come up with: Micro Terror JFET.pdf Knowing my luck, it probably won't be perfect as is, but you'll probably be able to get it the way you want with some tinkering. If you want more gain from the JFET stages, decrease the values of R39 and/or R40. The 12-volt supply is pro...

Well, 1. The only part value that I guessed on the schematic was C7, since I couldn't make out the part value in the pictures. However, if we compare with the values from https://gitlab.com/jofirel/uterror-amp/-/archive/master/uterror-amp-master.zip, we can see that I was spot on, despite the fact t...

One thing: you have R16 going to ground, rather than going to the bias voltage. I doubt that's how it is in the actual pedal.

I should have thought about it for a minute before I posted. As far as google will tell me, kvaker means "quaker," and as far as LTSpice will tell me, it is in fact a wah pedal. I wasn't sure what it was, since the other Kazan pedals that I've seen on this site also look quite wah-like. Af...

I can't help but love old Soviet-era effects, but I am incredibly confused about the schematic that plush uploaded. How does the negative voltage supply get to the circuit? What do R5 and R7 do? Are the "2200" capacitors in pF, nF, or uF? I wish I knew.

Looks lovely, but it's only for 230VAC, so I guess I'll have to do some searching for a 120VAC transformer that fits in the same spot.

I'd be willing to bet that the Atmel device is simply controlling the relays on the board. If so, cloning this beast shouldn't be horrifically difficult.

Absolutely, Frank. The TL072 is well-known for its glitchy behavior under clipping, so it's one that I don't exactly like using for non-linear applications, even though it's fairly quiet. One curiosity of mine is that the Orange CR120 uses TL072s in a non-linear fashion (actually having them clip by...

I doubt that this is where I'm supposed to put something like this, but I couldn't really find any other place to put it that made sense. I'm sure that this basic topic has been done to death, and I can already hear Dirk Hendrik's eyes rolling all the way over in Amsterdam :roll: , but the compariso...

I know that it's been more than a year since this thread was messed with, but I couldn't help myself. I went ahead and carefully studied the pictures of the Micro Terror pcb in order to try and make a schematic. Micro Terror Preamp.PNG I traced it as far as I could before I got to the giant blob of ...

I've been bitten by a bit of a DOD bug recently, and I've made a hobby of modeling the FX series of pedals in LTSpice to see how the tone is shaped, how they distort, et cetera. However, I'm having a bear of a time trying to model the FX-102 because the schematic that is commonly available is rather...

Oh, it is isolated, let me show you! *proceeds to blow all of the fuses in it* See, every output is now completely isolated!