Hi everyone,
As said above, I'd like to build a triple chorus based on Brian's GLAM project.
Largely inspired by the "J.HAIBLE Chorus" (http://jhaible.com/legacy/triple_chorus/triple_chorus.html (http://jhaible.com/legacy/triple_chorus/triple_chorus.html)), I'd like to sync LFO's and shift their phase 120° from each other to obtain a fat and lush effect.
Of course, I'd like to keep a speed control on modulation.
I'm sure it's not so hard, but I can't figure how to do that... :-[
This could be quite an undertaking. You can't easily swap in 3 Glams into the schematic because the original unit uses BBDs and a different power supply. You could possibly borrow ideas from the LFO and the general roadmap of the circuit, but it would take a bit of trial and error to get where you want.
Multiple delay chips and too many knobs though? That sounds right up my alley!
Theres a post on tagboard about the Glam and talk of how the PT2399 can take more than 5 volts for fewer ms in the minimum delay. It could be interesting see how three Glams work, one at 5, 6 and 6.5 (cant remember the max!) to see if that produces nice results. Maybe all with a drykill and mixed in with the dry :o Really like reading about these amazing beasts that id never heard of like the Haible circuits.
This sounds like a job for a synth LFO, some google results for LFO phase shifting mention muffwiggler...
Thanks for your replies, mates!
My idea was rather an adaptation with PT2399 based chorus than a simple chip swapping ;)
In fact, 3 GLAM-ish effect circuits with a tri-LFO modulation or a 3 GLAM circuits with each LFO sync'ed and shifted from each other.
I found some schematics like this one:
http://www.schmitzbits.de/triphase.html (http://www.schmitzbits.de/triphase.html)
Sounds like a good starting place. ;)
Anyway, I'm going to ask for infos on D.I.Y Synth forums.
I'll post here again if my project is successful! :D
Thanks again!
That LFO would work to a point, but it might not get the exact wobble you are looking for. The Haible chorus has a complicated (to me) LFO where there are actually two LFOs; the slow LFO is being "micro-modulated" by a faster LFO. I'm not sure what the voltage swing on the Haible LFO is, but it would have to be something to check to make sure that it doesn't swing past the parameters of the PT2399s. Could you rework that LFO to run off +9V rather than a -15V? That might help with the output and getting rid of any additional power supply circuitry. I might be off, but those are my thoughts.