VTL5C3

[GoranP]

Hello folks!

With vactrol prices being what they are lately, how can I roll my own acceptable substitute for a vtl5c3?

Datasheet states 1k light, 10M dark. The closest thing on ebay (at least that I've found) is a GL5506 which is a 2-5k light and 0.2M dark. Is that at least in the ballpark, functionwise? Obviously I'm gonna have no say in attack, decay and such...

[IvIark]

I've found in the past that the on resistance is more important, the off resistance has always seemed to me that anything "enough" will do and anything extra doesn't matter so much.  Of course it depends on the application but that is what I'd base my purchase on to experiment.  

Or you could try the Silonex NSL32SR3 which aren't too far away and should be much cheaper, but do have double the off resistance

[adstrum]

Just checked eBay for a NSL32SR3. I found one UK seller offering units at $9 but charging $75 to ship to Oz. WTF?.

[GoranP]

Well, at 4eur vs 6eur a pop (and double that with shipping), the silonex stuff is really equally beyond crazy for what it really is...

Unless someone has a decent lead on the 1k light ebay ldr, I may as well either forget the whole thing or bite the bullet. In case I do bite, these two have vastly different delays
http://www.banzaimusic.com/Vactec-VTL5C3-2.html
http://www.banzaimusic.com/Vactec-VTL5C3.html

How does one know which one to go for, say for an Uglyface? Vactrols are still a bit of a mystery to me and what exactly makes them work for any particular application i.e. how does the light value affect the operation. I suppose it's specific to any given circuit?

Silonex doesn't even specify this info:
http://www.banzaimusic.com/Silonex-NSL32.html

[IvIark]

I got some from Farnell for about £1.50 each a couple of years ago and just remembered they were cheaper than the Vactrols.  But looking at the original Ugly Face scheme it doesn't specify a Vactrol anyway, so I'd just be tempted to roll your own with any common LDR and see what happens.

[JaviCAP]

Really.... who knows.... ON ebay there's too a spanish seller that offers the vactrol you want for 5 euros / piece, but don't know how much about international s&h.

Anyway, for what I've seen, in circuits like the Mutron III, ldr values seem extremely critic, but on the Meatlball (highly modded Mutron), it seems that nearly every octcoupler you put in, will work.

The uglyface seems not really difficult, can't see trimmers to adjust the leds, si It would be a matter of minutes tu build the circuit and try one of the LDRs from tayda that you've got (60k light- 1M dark if I'm not wrong).

I bet it will work.

Marc, are still  Slonex octos in Farnell and are their s&h costs reasonable?

BR

[JaviCAP]

Oh, I answer myself: No, the s&h  and minimum order are not reasonable :)

Mark, you could suggest Bob from BitsBox to stock this items :)

BR

[GoranP]

Mark, I was gonna go for this one and it does specify the vactrol:

http://www.diystompboxes.com/smfforum/index.php?topic=70747.0

However you guys are right, it's not a high-parts-count build and I'm probably gonna build it and see what I can come up with rolling the ldrs I've got on hand.

@Javi: I'm planning to build a Lovetone clone collection in a not-too-distant future and that info sure is gonna come in handy. Thanks!

[IvIark]

Yes I've seen others which were based on it, But Tim Escobedo's original schematic didn't and he doesn't seem the type to bother with Vactrol's to me so I'd be surprised if he didn't come up with the original design with a simple LDR/LED combo.

[JaviCAP]

Goran, I'll build a Meatball on next month or July.  The board is quite easy but the offboard wiring is pure madness, so this time i'll get a Music Pcb "Meat Sphere" board, with all components onboard :P

It's expensive ($21 s&h included) but after the Mutron III and the Magnus Modulus, I'm fed to the teeth of massive amounts of pots, switches, offboard wirings and so on :P

BR