[sdiy] Buchla Lowpass Gate Switch

[Fernando de Izuzquiza]

Hi,

 > I found a 3P3T on-off-on switch at RS-components, 103-5552. Is this 
the
 > right one for PeterG's approach?

Sorry, I meant 3PDT. And I see now it's OK for PG's 292C (292C with 
mechanical switch)

Fernando



 > De: Fernando de Izuzquiza <fdi at ran.es>
 > Fecha: Sun, 15 Aug 2004 19:19:39 +0200
 > Para: synth-diy at dropmix.xs4all.nl
 > Asunto: Re: [sdiy] Buchla Lowpass Gate Switch
 >
 > Hi,
 >
 > In the Silonex site there is many info/examples about vactrol based
 > VCAs and many variations and methods to get better "muting", ways of
 > controlling the LED, etc.
 >
 > I think I will try different vactrols when I build mines (LPGs). Two
 > 5C3, a 5C3/2 and two Silonex also. The NSL-32SR3S it's fast and
 > selected for a tighter resistance value. I'd like to see how it works
 > on it...
 > I assume a faster vactrol will sound less Buchla.
 >
 > I found a 3P3T on-off-on switch at RS-components, 103-5552. Is this 
the
 > right one for PeterG's approach?
 >
 > Fernando
 >
 >
 >
 >> De: Peter Grenader <peter at buzzclick-music.com>
 >> Fecha: Wed, 11 Aug 2004 21:22:24 -0700
 >> Para: mark verbos <mverbos at earthlink.net>, synth diy
 >> <synth-diy at dropmix.xs4all.nl>
 >> Asunto: Re: [sdiy] Buchla Lowpass Gate Switch
 >>
 >> I might add that I didn't use single vac's on the rev Bs I've made,
 > but
 >> opted for the same single 3/2 dual element used in the rev c.  I did
 > this
 >> for cost reason's only.  As far as the performance, the sonic
 > characteristic
 >> of the two, the only differences I can hear is slightly less gain in
 >> amplitude operation and a bit more resonance in lowpass mode, which I
 > assume
 >> comes from the  properties of the FET.
 >>
 >> In any event, the rev B's FET allowed for the additional 
bleed-killing
 >> inverted feedback I added, I haven't been able to do this with the
 > rev c.
 >>
 >> - P
 >>
 >>
 >>
 >> Peter Grenader wrote:
 >>
 >>> Mark-
 >>>
 >>> I used a straight double on-off-on on my rev B's and I've got combo
 > in the
 >>> center. I'll be happy to post an mp3 to illustrate this!
 >>>
 >>> Have a look as the schematic- the top half of the switch puts 15K
 > across the
 >>> output of the second vactrol element, killing the filter.  The Rev C
 > does
 >>> the same thing, but does so with only 10k. The bottom half of the
 > rev B
 >>> switch increases the cap value, (.0047), just as C does. The
 > additional
 >>> third switch element in the rev C adds 15k to the input signal's
 > amplifier,
 >>> increasing it's gain.  Granted, the rev B doesn't do this, but this
 > addition
 >>> does not effect the mode switching, it just ups to output of
 > amplify-only
 >>> operation. This is why I didn't see that an on-on-on was required
 > and as it
 >>> turns out, it seems to work fine without one.
 >>>
 >>> - P
 >>>
 >>>
 >>>
 >>>> it actually doesn't save anything because the switch the rev B used
 > is a
 >>>> On-On-On switch, which is even more rare and pricey than the 3PDT
 > one!
 >>>> The reason i modded the rev C was because of price. I wanted a
 > cheap and
 >>>> simple solution. Also the wiring is easier than using multiple pole
 >>>> switches. Fewer wires, smaller switches that can be closer 
together,
 >>>> easier to get, cost less. Seems like an obvious choice to me, but I
 >>>> guess not for everyone...
 >>>>
 >>>> mark
 >>>
 >>
 >
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