[sdiy] European VTL5C3 group order update

[Peter Grenader]

We warned...slow is a VERY relative statement with Vactrols.

 I use the 5C3 singles in my state variable filter and in the morph
crossfader in the VCO.  I've got to bin them for decay before i sruff them
in the VCF poles and reserve only the fastest of those for that applicaiton.
The crossfader is a lot more tolerant of slowwwwww vacs.  In the filter
however.  if i pick the wrong one....the lowpass will take up to 2 1/2
SECONDS to fully close down after the frequency pot turned fully CCW, which
is a bit sucky.  I love the smoothness of vactrols more than most - but 2
1/2 seconds is like mashed potatoes in water.

In my binning, I see parts with a decays that vary between .15 to .9
seconds. That's a lot of tolarance.

So...it's all good, just don't be specing any critical timing requirements
unless you're prepared for less than a 30% yield. At $5 a pop, that can
hurt!

My test set up is arcane, but it's effective.  I've got a little variable
speed square wave gen, it's a Velloman PCB I've had laying around for years,
which drives an e-follower NPN with that into the vac led.  I'm driving it
fairly heavily with a 400 or so ohm current limiter. The resistive side of
the vac goes into a voltage divider. I hang a one scope probe there and the
other on the base of the emitter follower to determine the decay.  They are
then grouped together by like ranges in a little plastic egg-carton type
box. Piece of cake.  Slow ones go the the VCO, quicker ones to the filter.
This REALLY helped my throughput in assembly.





Jeff Farr wrote:

> Sorry to jump in unimformed.  Where in America can I order these?
> 
> On 12/23/05, Andre Majorel <amajorel at teaser.fr> wrote:
>> On 2005-12-22 15:18 -0500, Aaron Lanterman wrote:
>> 
>>> I'm in the US so I can easily order from them directly - I was
>>> planning to get some for my synthesizer class to be able to play
>>> with.
>>> 
>>> I've heard that the VTL5C3 and VTL5C3/2 are most common - what
>>> are the VTL5C2 and VTL5C4 used in? Should I pick up some of
>>> those too?
>> 
>> The VTL5C2 is slower than the VTL5C3. Charlie Lamm has built an
>> envelope follower that can take either :
>> 
>> http://www.charlielamm.com/synth/vactrolenv.php3
>> 
>> Scott Stites has used it in his phase shifter :
>> 
>> http://mypeoplepc.com/members/scottnoanh/slsdiy/id10.html
>> 
>> He wrote on the subject of VTL5C2 vs. VTL5C3 in the link I gave
>> last week :
>> 
>> http://www.the-gas-station.com/messages.cfm?thread_id=56949&lastdays=2000&
>> 
>> For the sake of disseminating knowledge, here's Scott's post :
>> 
>> | "Yeah, but what am I gonna do with all these VTL5C2's?"
>> |
>> | Lemme guess - BGMicro, right? =0)
>> |
>> | Obviously, the VTL5C3 and VTL5C3/2 are the 'prime' Vactrols for
>> | a lot of apps, due in part to the fact that, purely by glorius
>> | chance, the response curve closely matches the natural envelope
>> | of percussive attacks such as plucking, malleting, etc.
>> |
>> | But the lowly VTL5C2 can be quite a useful little guy to have
>> | around - it'll do all the stuff the VTL5C3 will do, just a lot
>> | 'squishier' - it's much slower on the draw, so to speak. But,
>> | for slow modulation, it's perfectly fine, and the squishiness of
>> | it can actually impart its own sound on what you're doing.
>> |
>> | Since you got a bunch of them, build a big-ass, multi-multi
>> | stage phase shifter with them - it can really sound good and is
>> | a fairly simple thing to do. I've proto'ed a 10 stage phaser
>> | that I like a lot (I call it the Lazy Phaser, because of the
>> | response of the VTL5C2's to fast transients - I wouldn't
>> | offically name it that out of deference to Konkuro =-D).
>> |
>> | Charlie Lamm has built a bitchin' sounding filter out of them,
>> | and they've been used in some compressors for years (DOD comes
>> | to mind). I've actually used them as the control element in
>> | simple yet very effective voltage controlled lag circuits. Don't
>> | toss'em, whatever you do, they'll come in handy one of these
>> | days.
>> |
>> | I've got some crude sound samples of my 10 stage VTL5C2 phaser
>> | on my page. It's been lying fallow on the breadboard as I've
>> | pursued other things, but I want to get back to it.
>> 
>> Regarding the VTL5C4, don't know what's its selling point is
>> compared to the VTL5C3 other than that it's been used in
>> compressors. Try a web search for "vtl5c4 jh"...
>> 
>> --
>> André Majorel <amajorel at teaser.fr>
>> http://www.teaser.fr/~amajorel/
>> 
>