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1) I wouldn't buy that one, unless you like to have buffered bypass instead of true bypass. You could use this one: https://www.musikding.de/3PDT-Board-set-of-3, though you would need to figure out what to attach where (and this one has a LED and LED resistor that are also on the PCB, so you need to choose which one to use).
2) Two LEDs for clipping and one as on/off indicator (not specified in the BOM). You could drill holes for the clipping LEDs (they might light up when you strum your guitar hard), but there's no need: they are for generating distortion.
3) Your choice: either buy PCB mount pots and solder them directly to the board, or 'regular' solder lug pots and wire them. This is DIY after all  .

You mean the bypass cap you can find on the FET's source, or emitter of a BJT, in some circuits? I would normally try to use an 'audio grade' electrolytic there, since it is involved in frequency shaping. I highly doubt that it would make any difference what electrolytic you use in that position. But, for me, it's part of the fun of DIY to select the components that give me the greatest building joy .

I would definitely recommend downloading the TapLFO3 datasheet from electric druid: https://electricdruid.net/product/taplfo3/. It has a lot of good tips and example circuits (including for filtering/buffering the output).

Edit: you probably would like to avoid going for rail-to-rail opamps to buffer a 0-4V LFO, but rather offset the signal to, e.g., 2-7V. But that depends, of course, what you want to drive with the LFO.

Sounds like a good spot to try a trimmer pot

Well, for using the StompLFO in a tremolo, it would. You would be able to tweak it such that perceived volume stays constant when you change depth. But ... it is a different chip from the TapLFO3 that is used in the Wavelord (and different number of pins). Downside of the StompLFO is that it has less waveforms, and it does not have a multiplier for the tap tempo, which is a problem if you like fast-but-in-sync-with-the-beat tremolo.

I have been daydreaming about this for a while ... and the best option would be to have both chips, with the TapLFO3 as master, with its clock feeding the StompLFO ... Then, on the other hand, maybe I don't need a synced tremolo all that bad. 

One more question about the taplfo IC... I see that with pin 8 on the IC, the output can go from 0-5 volts or be biased at 2.5 volts and have a bipolar output... With reference to ground, either option sounds like it's the same result... So, why is there a bipolar output with 2.5 volt bias option?

As far as I understand it, at max depth, both options will give you the exact same wave. The options start to differ when you decrease depth. With the offset at 2.5V, the center of the wave will remain at the same spot when you decrease depth, with unipolar, the center of the wave shifts when you decrease depth. What works best depends on the effect you're applying the LFO to. For a modulated filter, you may like the center frequency to stay in place when you decrease depth. For a tremolo, you might like unipolar better: at the right polarity, the perceived output volume will not change much when you tweak depth.

The StompLFO chip has a continuously adjustable offset, by the way. ElectricDruids FilterFX uses that in a very nice way. You can adjust the center frequency of the sweep, and with depth at zero have a foot pedal change the offset for a wah-type effect.

Yeah, it's probably there to separate the power line of the taplfo from the rest of the circuit. Apparently, 330 Ohm is too big here, given the current draw of the taplfo. 5.5V at the input of a 5V regulator would be insufficient to let it work properly. You could always sub something smaller for R28 (look at the datasheet for the regulator to see what input voltage it's happy with, and use Ohm's law).

There's no harm in trying them in a fuzz face ... (or other fuzzes). I played around a bit in the past with hfe around 50 for Q1 and around 20 for Q2, and got some very nice and useful overdriven sounds. Further, you can always use them as a Ge buffer stage or as Ge diodes ...

With all that said, there is very little benefit for Pharma to push out an ineffective or harmful drug. Sure, things slip between the cracks sometimes, but that is by far the exception to the rule.

Apparently not unheard of for pharmaceuticals to release a drug (that works, but might cause massive headaches or some other side effect) so they can release another one that will minimize the side effects of the first.. (or so I'm told by someone who did a thesis on this - I have no evidence).

It's pretty cynical to assume that side effects are actually purposefully designed into an otherwise effective drug. Pharma is pretty evil, but not as evil as the tobacco industry  . Without any evidence as support I would personally not put much faith in such a story.

... I am kinda iffy on the idea of being forced to be injected with something that might have unknown long term side effects. ...

Everybody should question forced injections, but I would be interested to learn which countries are actually going that way. I am in a risk group, and I'll personally take the known and unknown side effects of a professionally developed, tested, and risk-assessed vaccin over the already-known side effects of a covid infection any day.

The usual Muff suspects such as 2N5088, BC550C, BC549C, etc. sprint to mind. Anything NPN you can lay your hands on with a hfe in the 400-800 range. It might change the sound too much, or not enough, but it won't hurt to try, and doesn't cost much. Just watch the pinout of the transistors.

More gain as in more fuzziness? Since you socketed the transistors, it's easy to try some others. A higher hfe transistor in Q1 might give you more fuzz. If that does not work, you could try to switch places of the Q2 and Q3 transistors (since no two Ge transistors are exactly the same, that just might change the sound, for better or worse). Q4 is just for a little volume boost after the tone stack. I would not expect a different transistor there to make a difference, and certainly not to the fuzziness.

Is this circuit true-bypass switching? If it is, I would check the wiring first. Posting some gut shots might help someone spot the problem.

...actually, to quote Columbo, just one more thing...

I see that you are from a certain vintage 

On the finished photo again, it shows the labels on the two DPDT switches are reversed, Overdrive/Boost/Distortion for left switch (side A on the pcb) and Distortion/Boost/Overdrive (side B on pcb) - is this standard/correct, with both switches flicked left (as in photo) you'd get overdrive one side and distortion on the other. Or this another modification they've done? Just thinking of my own labelling being correct and understanding the pcb better. The diodes below switches do mirror each other on the pcb, so I think makes sense?

When in doubt, I always use a multimeter set for continuity. That will tell me which pads of the switches are connected to what (together with a look at the schematic). Then you have to realise that the switch poles are opposite to the position of the toggle (so switch to the right means that the left-most poles are connected). There is unfortunately nothing in the build doc to help you here, and no 'standard' way to do it. The build/labelling on the photo might be correct or it might not. Measure and you know  .

Hi - ok thanks. Does that mean you'd power it with 18v or 9v and then that part of the circuit doubles it internally?

As mjg said: if you use IC3, don't power it with 18v ... smoke will come out and bad fumes. There's no overvoltage protection on board, and max allowable voltage on charge pumps will be less than 18v (and you would have to worry even more about voltage ratings of caps).

It would not be too hard to bypass the charge pump part of the circuit, and run the circuit on a wall wart that puts out 9-18v. It is not explained in the build doc, as far as I can see, but the schematic helps.

The pedal will sound different at 9 and 18v. Not sure what is 'better'. On my to do list, I still have to try running a tubescreamer at LESS than 9v, just to get more 'stress' from the opamp and less contribution from the diodes. On YT, you're bound to find comparisons with 9-18v, so you can see what you like best.

What I get from the building instructions is that 18V with voltage doubler is the standard version as mr. PCB Mania intended. The switch on the photo you've found is obviously from an enthousiast who added a 'non-standard' switch. The PCB does not seem to anticipate such a switch, so that'll be a bit of a hack.