DEMO S.M.P.T.E. — a love letter to Frank Zappa & the Systech Harmonic Energizer

[Bricksnbeatles]

Interesting. I had no idea such high cap values could be used with color-cycling LEDs. I've used color-cycling LEDs in a few of my builds (both slow and fast varieties) and found that a 100nF and a 1nF do nicely. I had to be sure to take the power directly off the DC jack for the color-cycling LED too.

I’m sure a much smaller cap would have done just fine, but with the absurd amount of gain, I figured overkill would be a safe bet. When this thing is amplifying a narrow upper-midrange frequency band by like 24db or something like that, I don’t want to take a chance on it amplifying and residual μC noise too. I’ve done buffers with the color cycling leds as power indicators, and those just got a single 47nF cap iirc.
The cap being this large definitely has an impact on the color cycling, but mainly just in the sense that instead of each color taking around 2 seconds to cycle thru, red stays lit for around 2.5-3 seconds, and the transition from blue to violet is more like 1.5 seconds. Sorta like the difference between a sine wave and the throbby waveform of a univibe. Maybe I can take a video to show the difference in a bit.