Analog "bitcrusher" circuit: schematic questions and "improvements"

[NoahMeurer]

Thank you for your awesome reply! Definetly got me further as well. Here's a schematic as posted before: https://www.parasitstudio.se/uploads/2/4/4/9/2449159/sonic_reducer_pcb.pdf
I built it *almost* like the circuit shows except the feedback of IC2.1. I just used a 1.5k, 3.3k and a 50k pot since I didn't have all the three original components (15k, 33k and 500k pot). A friend of mine told me that this doesn't matter since I keep the ratio. Also, I sticked to the J201 JFET instead of the 2N5457 and used 1N914 diodes instead of the 1N4148 ones.

Regards

[bellebasaur]

I'm looking at the parasit studio schematic, and IC2.1 TL074 is acting as a comparator, to control the level of signals that is able to trigger the effect.

The stuff behind that is a pulse generator IC2.3 controlling the CD4066 switch.

I don't understand the R6 C4 low pass going into the TL074.1 though. It forms a low pass at 160Hz, doesn't that mean anything above the G string doesnt trigger the effect as well?
Actually i'm also confused what the effect of the signal coming from IC2.1 into IC2.3 does.


[edit] wait. ok, i been thinking(barely) so the comparator doesnt give any signals to IC2.3. it just slams to V or Gnd. depending on comparison. and 9V does nothing but 0V would sink the pulse circuit. turning off the effect when there is no input greater than reference of comparator.

I'm still wondering about that low pass though

[PRR]

> the R6 C4 low pass going into the TL074.1 though. It forms a low pass at 160Hz

The 100r is in series with a diode. So it isn't 100r.

Without actually analyzing, it is probably a rectifier. R6 C4 set the attack time, ~~1mS. C4 and R7 is the release/decay time, ~~22mS. Since there is gain of 470 in front, it is more a "signal present" detector than a precision measure.

With a sample/hold in the main audio path, I think any "low pass" notion is confusing. 

[bellebasaur]

The 100r is in series with a diode. So it isn't 100r.

Without actually analyzing, it is probably a rectifier. R6 C4 set the attack time, ~~1mS. C4 and R7 is the release/decay time, ~~22mS. Since there is gain of 470 in front, it is more a "signal present" detector than a precision measure. 

Ahh, okay, yea i see it now. The diode is a big DOH.
Thanks PRR!
I guess the attack time and decay times don't really matter as long as they're fast enough. Plus its going through that comparator flip flop.

preoccupied with whether it'll work well with my bass, all i could see were high pass low passes

[PRR]

> whether it'll work well with my bass

Close your eyes, double all capacitors.

Yes, this can't be an all-purpose Optimum. As you note, attack/release are not pitch but musical pacing. Bass tends to slower rise/fall but maybe not half. (A e-bass is not twice the length of a e-guitar! Acoustic, maybe twice?) If very determined, you could use two caps parallel everywhere, sockets or tack-soldered, and experimentally try one or both at each position. Or leave room for more/bigger caps but start with the guitar values, see where you think it wants "more".

[PRR]

me> A e-bass is not twice the length of a e-guitar! Acoustic, maybe twice?

Double bass 44", acoustic gitar like 25-1/2, 1.73X

Yes, 2X lower pitch cus mass is added and tension reduced.