Active Panny....Wah???!!!!

[Matthew Sanford]

In reference to this thread's stuff.

So, I'll get to phase on it later, but for an inverted thing a bit tremelo I made it a 4 in, 4 out thing. Started taping LDRs to LEDs, 4 really so I call it lDr. LED IV, and then I made two and created conjoined twins!




Among other things, thinking on these variable resistors in series, why not put a cap to ground at the end as an option to make them low pass filters? So I'm going to do that, still building, but a switch for each for choice. I'll have inverted LDRs, 2 to each out, so one should go down as the other goes up.




Using the 20k trimpot I can increase the voltage, though it reduces the range as it increases it, but not a bad thing necessarily. With it set reasonably to my mind (trim around 13k), testing one LDR shows range of about 12k to 706k, so I thought on 1n, 10n (ridiculous), maybe 2n, but I'm thinking a 3n3, should make it 68Hz-4100Hz about, so C2# on low through full range of a piano. Do you think that is a good setting? Maybe I should just put pin sockets for each so I can swap them out on a pedal when changing the trimpot value...or shoot, later a knob to choose between different values...or maybe start with a baby and switches to add ones in parallel...

So the world is wide open! I'm going to try it with 3n3 and get sounds for you though, hopefully this week.

[duck_arse]

the sound of Los Alamos.

[Matthew Sanford]

Nearly done with this thing. I put Jack's FET buffers at each input and output, so 8 of these



I used the taps on the jacks to bring unused ones signals through 1ks to other jacks, 2&3 to 1, &4 to 2. Also switches to cap->ground for variable LPFs prior to output FET.
Block diagram


And Panny like this



With one in one out it's essentially a tremolo, but at a very fast rate it gets resonant I guess with some low volume odd pitches, not sure why...

Right now for the LPF 1n was nothing, 101n (parallel tack on) was eh (done on 1 & 2), then 2u2 tacked on 3 & 4 added a whole new depth. I realized I have a 3 pole (4->2->1) and 2 pole (3->1) on the output, how should I cap them? Shelf with same or various poles?