AASft21stC Phase Shifter

[fonik]

hi all,

i built the phase shifter from the 'An Analog Synthesizer for the 21st Century' book, today referring to page35, current source. it's the same source thomas used for other projects as well: inverting summer, NPN, PNP.

i now have a problem: the input of a LFO from -3.5V to +3.5V results in 0.02V to 0.1V at the base of the NPN. could/should this be? after a quick mental calculation i would say yes. however the 2N3904 is obviously doing nothing, i constantly read 0V at the base of the subsequent PNP.

so if anyone would have the time and fancy taking a look at the schematic, giving me a hint... that would be great.

[Tim Servo]

Hey Matthias,

Did you ever get your AS21C Phase Shifter working? I'm thinking of tackling that as the next Magic Smoke project, and I'm wondering if you had any reviews of the sound / performance. If you haven't gotten it working yet, I should be breadboarding one in about a week so maybe I can help you in troubleshooting yours.


Tim (gotta go buy some 13700s) Servo

[fonik]

no, i didn't - but i did not try that hard. i got sidetracked somehow...

[fonik]

took some time, didn't it? this project was hidden in a box for more than a year now, but yesterday i finally troubleshooted it, and got it working nicely (i made two errors on the CV circuitry, which caused the OTAs to always stay open). will upload soundsamples soon... thank you , thomas.

i hope i did not get anyone from building this module. just build it. i like it.

[fonik]

soundsamples here:
http://electro-music.com/forum/topic-18436-27.html

[Tim Servo]

Hey Fonik,

LOVE the sound samples! Nice work. I've been meaning to put one of these together for a LONG time, but you've provided me with some extra incentive.

Tim (phasey shifty) Servo

[ungleichklang]