what's your favorite optical compressor build?

[Boogdish]

I'm trying to figure out what to build next.  I have no compressor and I've never dealt with vactrols/ldrs before and so I'm thinking optical compressor. 

So what's your favorite one you've built or played through that I might be able to find a schematic for?

[MartyMart]

You should try the "Flatline" which is here if you do a search, including a neat little stripboard version.
It's really good and serves as a VERY loud boost also if you need it to.
The Flatline is quite a simple build too.
The Graig Anderton compressor is also opto, using the now hard to get CLM6000 but I think that
smallbear has them, one caveat is that it runs on a +9/-9 power supply, so you need either 2 batteries
or a small PSU supplying both voltage rails - watch that mains stuff !!!
There's also the "LA Light" but that's more of a Limiter than a compressor, works quite well though.

Marty.

[Mark Hammer]

Jack Orman and Thomas Henry had a slight redesign of the Anderton EPFM compressor that they called the "Whisper" compressor, and sold through Midwest Analog for a while (now defunct).  The Whisper included a BMP-style tone control tocompensate for the natural properties of heavy compression.  Not sure if it is still posted around or whether Jack and Thomas would be interested in making it public again.

Although Anderton used the CLM6000 in many designs, and chose it for its resistance range and rate-of0change characteristics, there are other more available commercial units that behave in a similar enough way that there is negligible difference in how it sounds.  The Silonex NSL-32 is probably an acceptable sub.  Happily, the manner in which the EPFM/Whisper design uses the CLM6000 allows for considerable flexibility in adjusting the way in which it changes gain, making it very easy to offset differences in LDR properties with a change in one fixed resistor here or there.

There are two very nice things about optos: 1) you can drive the bejeezus out of them, unlike OTAs and FETs, and they don't care, and 2) their "settling time" back to full resistance tends to be sluggish, which makes them more immune to the envelope ripple during the tail of notes that so often plagues envelope-controlled devices.

[jayp5150]

Jack Orman and Thomas Henry had a slight redesign of the Anderton EPFM compressor that they called the "Whisper" compressor, and sold through Midwest Analog for a while (now defunct).  The Whisper included a BMP-style tone control tocompensate for the natural properties of heavy compression.  Not sure if it is still posted around or whether Jack and Thomas would be interested in making it public again.

Although Anderton used the CLM6000 in many designs, and chose it for its resistance range and rate-of0change characteristics, there are other more available commercial units that behave in a similar enough way that there is negligible difference in how it sounds.  The Silonex NSL-32 is probably an acceptable sub.  Happily, the manner in which the EPFM/Whisper design uses the CLM6000 allows for considerable flexibility in adjusting the way in which it changes gain, making it very easy to offset differences in LDR properties with a change in one fixed resistor here or there.

There are two very nice things about optos: 1) you can drive the bejeezus out of them, unlike OTAs and FETs, and they don't care, and 2) their "settling time" back to full resistance tends to be sluggish, which makes them more immune to the envelope ripple during the tail of notes that so often plagues envelope-controlled devices.

There are actually partial and complete Whisper projects at smallbear http://www.smallbearelec.com/Categories.bok?category=Kits+And+Designs

[Mark Hammer]

Cool!