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Me and the Mrs. with some metalheads

You haven't heard this from me, but I often just make a big blob of solder that covers all pins on one side of an IC such as the one in the video above. Use flux liberally, you'll clean it later. Then - while the solder is liquid, of course - I lift that IC side up, just off the board. I use...

I'll always tell whoever is listening that SMD isn't nearly as hard as it may seem. You just need a fine-tipped soldering iron, thin solder wire (perhaps <0.5mm) and maybe some flux. Good eyes aren't even mandatory: you can do it under a magnifying glass lamp, or use some cheap magnifying...

No idea. Is the vari-cap grounded in the radio? Then maybe, but you'd need an op amp with a wide bandwidth (tens of MHz), so it can still have significant gain (10x or so) at AM radio frequencies (up to almost 2MHz).

^ Depends on the circuit. Panning adds a significant series resistance when not fully at one end or the other. The circuit above acts like a pure cap with no series resistance.

I read somewhere that there's a floating version, but haven't investigated further.

If you've used (or thought about using) something like a rotary switch to switch between different capacitor values in a circuit, you might want to consider a continuously variable "active cap" instead. It can be made with a simple pot and a couple of op amps that form a capacitance multiplier...

I used to use no-clean but stopped. Rosin just works better for me, especially on non-perfect, somewhat oxidized stuff such as older parts or wires or PCBs. And it smells a lot better too, as a bonus. Oh the other hand, if I do want to clean "no-clean" flux (because it still looks greasy and...

99% isopropyl alcohol from a dispenser and a standard-issue short-and-stiff-bristled brush from the dollar store (natural fibers, as opposed to plastic, if I can find one). I cut the bristles shorter if it helps. I pat the wet board with (allegedly) lint-free Kleenex to wick as much...

I'm in Canada and my "local" PCB manufacturer is JLCPCB.

The second picture will do a much better job of filtering power supply noise because the series resistor R7 forms a low pass filter with C4. This comes at the cost of a slight voltage drop across R7. With most pedals drawing only a few mA though, the drop is very minimal: 10 ohms x 10mA = 100mV...

Don't people mostly use AC adapters to power pedals these days? In which case super low power is not really important... Might as well use something like an LM4808 if you can spare 1mA idle. It's also a max 6V part, so it would need a regulator.

I tested an OPA2310 the other day to see if it makes sense as a headphone amp, given its high output current capability (150mA) and very low idle current (~165uA per channel). Great for battery power! Only problem is that it doesn't take more than a 6V supply. But a low quiescent voltage...

MLCCs (with an X5R/X7R dielectric) are fine in the audio path (certainly as far as pedals go, at least) as long as any voltage across them is far less than their rated voltage. This avoids voltage-dependent loss of capacitance and distortion. I use 10% tolerance X7R rated at 50V (or more) and...

Check R44 if the ICs don't get power. Also, make sure it's 100 ohms and not 100k.

I feel that this style is the most reliable of them all, but it needs a bit more space than other designs:

The caps do not contribute noise. The 3 circuits have the same output level and frequency response. Not sure I understand the last question.

I thought the most common, garden variety log type is 10% at mid travel. Is this not the case?

The first 10 probably means that you get 10% of the total value when it's at the half rotation point, measured between the CW lug and middle (it's the opposite of a log pot, which would be 10% measured from CCW to middle)

yes