flickr set by Yotsuba&!
(click for more)
Top: Buchla 227e back panel module for 200e
"boat power."
Middle: Buchla 200e Vactrols
"non-isolated vactrols, a couple of many used in the 227e System Interface module."
Bottom: Buchla 200e with new modules freshly installed
"july 2009"
nice pic
ReplyDeletenon-isolated vactrols, riiight...
ReplyDeleteI mean I'm curious why Don have chosen to use LED/LDR pairs instead of vactrols. Was it an inherent design from 200 series? were there not enough vactrols available? did he use red LEDs on purpose (different LED colors give different response curves)?.. etc etc.
ReplyDeletethe old ones needed to be selected for various responses.. these can be "tuned" according to the distance of the LED from the photocell
ReplyDeletei was under the impression that an LED/LDR pair IS a vactrol. these ones are not isolated from one another, hence the description. he DOES use self-contained vactrols as well- in fact, more often than this open style in the modules i've seen. i'll post another picture to my flickr.
ReplyDeleteThat thing is a BEAUTY!
ReplyDeletemmm, open vactrols. You wouldn't expect that on such a high end synth.
ReplyDeleteWith two next to each other, won't it have crosstalk.
Jena_Mu6, exactly, that's what surprised me.
ReplyDeleteProbably they are used to get cross-talk between two parameters.
Yotsuba&!, could you tell us what modules use those optopairs please? I might guess Source of Uncertainty does.
oh... i'd have to take it apart to check. eventually i will rearrange. i just noticed i used the wrong title for the first pic, just fixed it on flickr.
ReplyDeleteThere are "real" upppercase "V" Vactrols™ in the 292e, and probably other places in the 200e. There are vactrols like the ones pictured here in many other places. There are also vactrols like the ones pictured here, but with little opaque plastic cases glued over them in other modules.
ReplyDeletefun fact: on a given 227e channel the swirl leds are in the same circuit path as the associated vactrols for the 4-way output on the same channel. so what you see externally moving around the knob is the same as what's firing off internally in the (non-isolated) vactrol circuit.
ReplyDelete