I have never heard of tying the "middle point" to ground or Vref. I can't imagine that working, as any audio will just go to ground or Vref, right? Can you source that idea? Where did you hear it?

For those two caps you need bipolar. You can fake it: two 20uf caps with the - sides soldered together equal a 10uf BP cap.

You can use mono jacks for "clean" and "CV."

Yes, momentary is momentary, says so in the BOM.

MBB is unusual, doubtful you need them.

Clean is a separate, slightly reduced clean output that only works when the pedal is engaged.

The CV is a jack for Control Voltage, 0-5V.
These last two answers from the Dead End FX doc for their version.

The two schematics are identical regarding the diodes. Two ways of drawing the same thing, switching diodes between feedback loop and output of the opamp to ref/VB. One schematic has a small cap, 47pf, in the feedback loop, always a good idea in these kind of things. The other has a 100n DC blocking...

One more member reporting forum down 24 hrs. Same message.

The PCB has two pads on the right marked 9v and ground, which go to the power jack, red and black wires we usually use here. The PCB has pads near the bottom marked In, Ground, Ctrl, (then two where you have already soldered Diode 5) and Out The Switch daughter board has pads for In, Fx in, LED Grou...

When they say "check solder joints" they don't mean just look, but go over them again with the iron, reheat to make sure everything is connected. (not too long near the transistor, but your is socketed, sockets are often not good connections. Make sure it is firmly in place.) Often I've ha...

Opto? LDR takes place of pot, pot adjusts brightness of LED. Will have to be arranged with series resistor to set minimum and parallel resistor to set max.

Why a charge pump for a buffer? If you wanted lots of clean boost I would understand, but buffering means gain around 1, so unless you are buffering a signal already close to 30v(!) that is wasted headroom and parts and power and... an invitation for trouble... Maybe it's part of something bigger?

Always good to try different tapers. I have built a number of these. I like to change the clipping diodes for MOSFETs plus diodes, or even a single mosfet for assymetry... or really any single clipper for assymetry. Also playing with the value (and taper) of the gain pot can give you a different ran...

Sorry I didn''t notice you worked from the smaller layout. Still the questions are why is the base less than .6v above the emitter... and check the off board wiring...and can you audio probe it....

So I see you took two rows off the layout, and that should be okay, the top two rows just made a nice arrangement for the diodes, and it looks like you adjusted things. I think I see a missing cut: it should be in your second from the to row, fourth column...maybe part of your "adjustments?&quo...

The B and E of the transistors should be "one diode drop" apart, about .6v. Audio probe might help find where things are going wrong.

Any insight into the feedback(?) between the two transistors, R9 and C2?

The first transistor is a booster. Then there is a "T" filter that cuts bass. The second transistor is a gain recovery stage. So your signal is super hot and super aigue.

Spltter/Blender is one very useful thing you will find many uses for. You can find them on the strip board layout sites. The simple one shown above should do the trick. Some have two "send/return" loops so you can also pan between two effects.

Is that booster schematic right? very unusual...?

If it sound right it is right. The bulb isn't to read by, so as long as you like the sound, no need to go trying to brighten it. Though there are ways to do that . Your unit seems to be missing the light shield, the little (shiny) metal box that encloses the bulb+LDRs. That will deepen the sound a b...

The resistor in series is a cautious thing. Maybe 100ohms? Just something in case. It will drop some voltage, your circuit won't get all the juice it should. The power supply voltage seems a bit low for a univibe, and yes that transformer looks modern... But you say it was working, so it's big enoug...

You're new enough here that somebody has to say: be careful with that power transformer and the AC! You will get some people who have done this exact repair and will tell you what to be careful about when powering this up again. I've built clones but never messed with an original unit with an issue ...