Photocouplers By Macron

[smallbearelec]

http://www.macron.com.hk

After a lot of factory back-and-forth and major help with testing and QA from Ed Rembold,  work-alikes of the VTL5C2, C3, C4 are now available at reasonable prices. They are fairly consistent for this kind of part. I will be working on getting dual-LDR types, as well as clones of the C9 and C10.

http://www.smallbearelec.com/servlet/Detail?no=1255

Regards
SD

[armdnrdy]

Great job Steve! Thanks! If you come across any C6's there's a project or two out there that demands them. People have tried "rolling their own" with less than stellar results.

[liquids]

Great job Steve! Thanks! If you come across any C6's there's a project or two out there that demands them. People have tried "rolling their own" with less than stellar results.

Yeah - of note, the Pigtronix compressors use the C6, as far as I know (or at least some of them, or have at one point).  I think that is the main draw, and for 'plug and play' parts, that's the one people want for their clones.

According to datasheet, the C6 is spec'd at 3.5ms to get to 63% final ON resistance (very fast on like the C3), and turn off is 1Meg by 50ms - quick to reach a high resistance off for an opto component.

C9 type is similar to a point - but it's off is "only at 100k" by the same measure of time - 50ms.  Different 'material' and other specs listed of course (current, and the curve tell further details)

I imagine if you could provide a opto comparable to the C6 for Pigtronix via Macon (and to us diyers), you'd have some sure buisness on hand...unless they went straight to Macon...

The C3 is a great part for trems though, and also for all but the most demanding compressor needs and designs.  For opto compressors and trems, the opto component's specs really makes or breaks it.

===================

Then again, from the traces schematic seen, the Pigtronix philosophers tone straps a HUGE cap across the LED side of the of opto.
Since I'm no EE and have only messed with the John Hollis sort of design directly so I find that kind of funny(also FWR, cap across it, etc)..though I may not understand the Pigtronix design in that it's different than that too.   

It may also be that the optos 'off' speed and curve is moot in conjunction with that cap, or the cap could be tweaked (reduce in size) to compensate for a different, slower opto...it's all a balancing act...but from my experience, it's easier to start with an extremely fast opto and 'slow' it's speed and curve to taste (though there are limiting factors), since you can't exactly make the any faster to respond than it does inherently, to my very limited knowledge.
Again, a balancing act.

A side note PS: someone should consider a not-simple design that has variable blending of opto compression, OTA compression, and clean/uncompressed.  There's also the THAT chips as an addition/alternative in that mix; or, as an instead.    

Welcome to the world of my breadboard and bench tinkering.........................uh, well, at least taht was up to the last time I was in front of it.