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Over at General Guitar Gadgets we can find the Maestro FZ-1S, a silicon version of the FZ-1 (click on the link). The circuits surrounding Q3, Q4 and diode clippers Q5 & Q6 look very familiar.

OK, I think we've wandered far enough off topic. Look for SM caps on eBay. Shop around because some are way overpriced. I bought a bunch from my local electronics store for $0.50 ea a while back and now they're all gone.

Dude, you are on a roll!

Most excellent build!

Q1 (my schematic) is much better as a MOSFET than as a JFET. I thought about it, but JFETs don't sound good if we overdrive the gate and that's what would happen in this circuit. MOSFET are immune from gate overdrive. I guess you'll have to settle for using tropical fish to satisfy the Mojo. ;)

In general, I consider 1uF film & 1uF tantalum to be equivalent. In theory, film caps are less noisy than tantalum because their leakage is lower. However, the leakage in tantalum is so low that I doubt the noise will be detectable. Some hard-core audiophiles might be able to tell the...

Aluminum caps have loose initial tolerance and tend to run on the high side. I just pulled a 2.2uF aluminum cap out of a Rat and it measured 2.3uF. I'm putting a tantalum in its place that measures 2.18uF. When analyzing the feedback network, we can't assume that the opamp has unlimited gain...

I think the designers had a MOSFETish.

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 don't know if the brand matters. I have Mot & Nat'l. GBW is definitely one of the factors affecting tone.

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...

From MOBA, the Museum of Bad Art.

It's in the equations in post #1. Vt, the thermal voltage, is a characteristic of semiconductor physics. At room temp it's 26mV. We multiply Vt by the shape constant "n" that lets us fine tune the shape of the exponential I/V curve. n is usually very close to 2. 2 x 26 = 52.

Thanks, Ginsly, I had not seen that. Puts things in a completely different light. I edited post #32 accordingly. I can see why they used a B-taper pot for ATTACK, because with A-taper, everything below noon would be useless. I'd like to figure out a way to fiddle the 2nd stage bias without...

Just to be clear, the Overcast is a clone of a the California version of the BossTone. Let's do a little circuit analysis. We'll start with the SUSTAIN knob dimed, its resistance at zero. R4 & R5 both connect to Vcc. Q1 has a little bit of local negative feedback via R2 and a little bit via...

It's still on the list of things to do...

Phill in Oz recommended this pedal to me and I thank him for that. He suggested trying red LEDs in place of the 1N4003s. Definitely louder. Less compression. At low bias settings, the LEDs don't conduct. So then I tried some low-leakage Ge diodes (ITT GD012). More compression, less volume...

I wrap the wire around the hole so it stays put while I solder it. As long as there is enough solder to encapsulate the joint, it's good. I've had to unsolder leads that were attached that way, and they don't come apart easily. Where leads go through a hole in a PCB or Vero, I fill the hole...

Pretty much. Metal film, wire-wound or even carbon comp would work.

It's good enough to feed to an auto-router.