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Incidentally, the Focusrite compounder uses a Silonex vactrol in the
same configuration as the Buchla for it's gate circuit. The same box
has a limiter based on a Vactrol that uses a complimentary schem. The
signal is inverted, then the so called shunt mode is used on both
halves, then they're re-combined. I guess this is similar to the
series/shunt mode. of course that's not practical in a lopass gate. a
balanced VCF, ha.<br>
<br>
Mark<br>
<br>
<br>
<br>
Fernando de Izuzquiza wrote:<br>
<blockquote type="cite"
cite="mid49E868C4-EEDF-11D8-9B6F-00039372027A@ran.es">Hi,
<br>
<br>
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.
<br>
<br>
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...
<br>
I assume a faster vactrol will sound less Buchla.<!-- Geneva -->
<br>
<br>
I found a 3P3T on-off-on switch at RS-components, 103-5552. Is this
the right one for PeterG's approach?
<br>
<br>
Fernando
<br>
<br>
<br>
<br>
> De: Peter Grenader <a class="moz-txt-link-rfc2396E" href="mailto:peter@buzzclick-music.com"><peter@buzzclick-music.com></a>
<br>
> Fecha: Wed, 11 Aug 2004 21:22:24 -0700
<br>
> Para: mark verbos <a class="moz-txt-link-rfc2396E" href="mailto:mverbos@earthlink.net"><mverbos@earthlink.net></a>, synth diy <br>
> <a class="moz-txt-link-rfc2396E" href="mailto:synth-diy@dropmix.xs4all.nl"><synth-diy@dropmix.xs4all.nl></a>
<br>
> Asunto: Re: [sdiy] Buchla Lowpass Gate Switch
<br>
> <br>
> I might add that I didn't use single vac's on the rev Bs I've
made,
but
<br>
> opted for the same single 3/2 dual element used in the rev c. I
did
this
<br>
> for cost reason's only. As far as the performance, the sonic
characteristic
<br>
> of the two, the only differences I can hear is slightly less gain
in
<br>
> amplitude operation and a bit more resonance in lowpass mode,
which
I assume
<br>
> comes from the properties of the FET.
<br>
> <br>
> In any event, the rev B's FET allowed for the additional
bleed-killing
<br>
> inverted feedback I added, I haven't been able to do this with the
rev c.
<br>
> <br>
> - P
<br>
> <br>
> <br>
> <br>
> Peter Grenader wrote:
<br>
> <br>
>> Mark-
<br>
>> <br>
>> I used a straight double on-off-on on my rev B's and I've got
combo
in the
<br>
>> center. I'll be happy to post an mp3 to illustrate this!
<br>
>> <br>
>> Have a look as the schematic- the top half of the switch puts
15K
across the
<br>
>> output of the second vactrol element, killing the filter. The
Rev
C does
<br>
>> the same thing, but does so with only 10k. The bottom half of
the
rev B
<br>
>> switch increases the cap value, (.0047), just as C does. The
additional
<br>
>> third switch element in the rev C adds 15k to the input
signal's
amplifier,
<br>
>> increasing it's gain. Granted, the rev B doesn't do this, but
this
addition
<br>
>> does not effect the mode switching, it just ups to output of
amplify-only
<br>
>> operation. This is why I didn't see that an on-on-on was
required
and as it
<br>
>> turns out, it seems to work fine without one.
<br>
>> <br>
>> - P
<br>
>> <br>
>> <br>
>> <br>
>>> it actually doesn't save anything because the switch the
rev B
used is a
<br>
>>> On-On-On switch, which is even more rare and pricey than
the 3PDT
one!
<br>
>>> The reason i modded the rev C was because of price. I
wanted a
cheap and
<br>
>>> simple solution. Also the wiring is easier than using
multiple pole
<br>
>>> switches. Fewer wires, smaller switches that can be closer
together,
<br>
>>> easier to get, cost less. Seems like an obvious choice to
me, but I
<br>
>>> guess not for everyone...
<br>
>>> <br>
>>> mark
<br>
>> <br>
> <br>
</blockquote>
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