Hello, I'm new to the board, but very experienced with designing, modding and building effects pedals. I just thought I would pass along some mods for the BYOC Tremolo.
When I built mine, I didn't think the Tremolo rate went high enough compared to the tremolo circuits in popular Fender amps. Using a circuit analysis program, I modeled the tube-based circuit from a Fender Deluxe Reverb amp and found the rate went from 3.75 Hz to 12.5 Hz. Similarly, modeling the oscillator in the BYOC Tremolo, which is based on the "Improved EA Tremolo", I found that the rate ranges from about 1.75 Hz to 8.25 Hz.
To fix this, simply replace C7 and C8 with 0.47uF capacitors. The range then becomes about 3 Hz to 13 Hz. If you look at the board, towards the top, just below the Rate control are three 1uF caps in a row. Replace the two caps on the outside (closest to the 1K and 15K resistors) with the 0.47uF caps.
Also, C4, the 10uF AC coupling cap to the 100K level control, does not need to be such a large value. I eliminated the electrolytic capacitor and changed mine to a 0.47uF cap. Even with a 0.47uF cap, the circuit will pass all frequencies above 3.38 Hz. If you don't have a 0.47uF handy, you can go with an even smaller cap. 0.1uF will still pass all frequencies above 16 Hz, still well below the lowest note on a bass guitar.
Likewise C2, the 10uF AC coupling cap between the two transistor stages can be replaced. In the EA Tremolo schematic, there is a 10uF capacitor in series with a 0.22uF capacitor. I'm not sure why this was done since the series combination just becomes 0.215uF, so a single 0.22uF cap would suffice. In the BYOC Tremolo, a single 10uF cap was used. In reality this should be a 0.22uF to match the EA Tremolo schematic, thus eliminating the 10uF electrolytic from the signal chain.
I've attached a picture identifying the caps to change. In mine, I just made them all 0.47uF.
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