Does Buchla roll his own Vactrols now?

[Ricko]

Am I right in thinking that Buchla himself no longer uses manufactured Vactrols but rolls his own using red resistors and some photoresistor? See

http://www.flickr.com/photos/adeneko/3775716262/in/set-72157621777322235/

and

http://www.flickr.com/photos/adeneko/3775690982/in/set-72157621777322235/

Is this just a price issue?

[Boogdish]

That definitely looks like LEDs pointed at LDRs.

It might just be a price issue, but it might also be an issue of needing a value for his LDR that he couldn't easily find in a prepackaged vactrol. Also, I noticed that the LED has some space between it and the LDR, perhaps he has experimented and found that he likes the sound better when it's not a perfect coupling and he does it for this reason.

I'm surprised there's no covering over them to keep ambient light from interfering. It would just take a little bit of shrink tubing.

[cbm]

For the classic Low Pass Gate, e.g. 292e, there are still Perkins-Elmers Vactrols VTL5C3 used. In places where gain needs to be controlled, but the specific ringing characteristics associated with the VTL5C3 aren't required, there are home-grown vactrols used.

[xpander]

bumping an ancient thread, you missed the close-up photo from my buchla set:

[snebenan]

Comparing the Perkin Elmer datasheets and the specifications for photoresitors there is a major difference in range of resistance.

VTL5C3: 1,5 Ohm -> 30 kOhm; (10MOhm when OFF for 10sec)

Photo Cells usually are in many different ranges, but most seems to go from x k Ohm to 3x kOhm.

Example: 6k->18k, 24k-72k, 4k->12k etc.

So as I see it there is a major difference in the dynamic resistor range.

Anyone tried to do stuff with their own rolled "vactrols" and care to share the specs of the leds and ldr's used?
//s