[sdiy] Yet another 292c Lowpass Gate audio sample uplaoded

[mark verbos]

I have not tried it, but the data sheets show that VTL5C3 has a turn on 
time of 2.5ms and a turn off time of 35 ms.

that's attack and decay to you and me.

the VTL5C4 has 6ms and 1.5ms
VTL5C2 has 7ms and 150ms

then, there is the resistance

VTL5C3   5k - 10M
VTL5C4 125 ohm - 400k
VTL5C2 2.5k - 1M

so, that being said.... you could use a VTL5C2 if you change the caps 
and resistors around it to make the ratios stay the same. You will have 
a significantly slower response though. i think you should use that one 
for an opto-compressor. 150ms is a really long minimum decay. The attack 
is kinda slow too.  In a vocal compressor, it will sound nice though. 
"Smooth" they call it. ;)

mark



Scott Stites wrote:

>Hi,
>I've been wondering - has anyone tried any Vactrols other than the VTL5C3 or
>VTL5C3/2 with the Low Pass Gate?  Specifically, I have some VTL5C2's on
>hand.  I figure that (obviously) different Vactrols will give quite
>different response curves.  Question is, is this a good, bad or 'beauty is
>in the eye of the beer holder' type of response?
>
>Keith, Mark, Peter - ever tried this?
>
>Thanks,
>Scott
>
>
>----- Original Message -----
>From: Peter Grenader <petergrenader at mksound.com>
>To: <synth-diy at dropmix.xs4all.nl>; <keithw at cix.compulink.co.uk>
>Sent: Monday, October 14, 2002 11:28 PM
>Subject: [sdiy] Yet another 292c Lowpass Gate audio sample uplaoded
>
>
>>Peoples,
>>
>>To augment Mr. Winstanley's Lowpass Gate soundfile, I have added one of my
>>own to my site which gives an example of the 292c circuit controlled by an
>>extremely short transcient-type  envelope.
>>
>>Two things will be instantly evident when you hear it:
>>
>>1)  No pop.  Do the same thing using a standard VCA,  with an envelope as
>>short as the one I have used and the usual VCA crack*pop*snap will be
>>
>heard
>
>>as it opens and reacts to the voltage applied.  The vactrol in the lowpass
>>gate by comparison affords a slight smoothing of control voltages as the
>>
>led
>
>>turns on.
>>
>>2) The ringing in 'combo' mode.  When the Low pass gate is set so that the
>>switch is on the middle position, one hears a mix of the standard VCA and
>>the low pass gate in equal amouts.  The net effect of this is a
>>
>wonderfully
>
>>natural sounding ringing  which is very audiblet with short envelopes like
>>I've used here  Chalk this up to the vactrol LED now dimming off and the
>>removal of the .0047 cap within the circuit.
>>
>>In the ate used in this sample I used polystyrene's for all caps which are
>>directly related to the audio path. The other two are combinations of
>>different types of caps in these places which was done intentionally to
>>
>give
>
>>each a slightly different persoanlity.  I can't tel from Kieth's picture
>>which type are on his, but they sound like mylars (one of mine uses those
>>
>as
>
>>well).
>>
>>Another application hint for the lowpass gate is setting the output level
>>
>of
>
>>the control source you're using to open it with to the bare minimum
>>
>required
>
>>to turn on the led in the vactrol - just a touch past the signal being too
>>low to excite and open the gate.  I usually use my Blacet EGs for the
>>
>LPGs,
>
>>where John's output level pots come in very handy for just this.  Using
>>
>too
>
>>much juice will cause a little clipping.  Backing it off will yield what
>>you'll hear in this sample.  I assume this is due to the signal levels of
>>the Buchla the circuit was designed for.
>>
>>To give this a listen, go here:
>>
>>http://www.allegrobikes.com/synth.html
>>
>>click on 'Son of Frankensynth"
>>
>>Scroll down to Homebrew modules link
>>
>>Scroll down to the Low Pass Gate listing on that new page
>>
>>click on the 'submit to the LPG' button and you will be directed the the
>>correct download link for the soundfile.
>>
>>To jump there immediately, simply go to:
>>
>>www.allegrobikes.com/lpg.html
>>
>>enjoy.
>>
>>or not.
>>
>>P
>>
>>
>>
>
>