Anyone tried out this compressor circuit?...

[SolderBoy]

http://www.fortunecity.com/tinpan/humperdinck/223/blackb.gif

A vintage compressor from 1977 housed in a black box(hence the name!) The circuit smooths out the peaks generated by the guitar. It uses a red-led(5mm) and a LDR(light depending resistor) The LDR is a penny-size thing with two legs! They are placed close to each other and are isolated against external light by black cloth or paper (photopaper?)
Uses high gain transistors-BC 209C(=BC109C)

looks interesting...

[SolderBoy]

Hmm...  Just tried that link, and it didn't work for some reason...

This is where I found the schematic...

http://www.fortunecity.com/tinpan/humperdinck/223/effect.htm

Scroll down to "black box sustain", (under "compressors" funnily enough!)   :?

Can I expect fast attack times with an LED/LDR arrangment (was thinking of souping this up with an NSL32 or something), or would I better off with a fet (ala carlin etc.)

any thoughts folks?

[J. Luja]

doesn't look like it'll work as drawn -that first 220k should probably connect to the second transistor's emitter instead of ground. Actually, it's basically a copy of the colorsound supasustain
http://www.generalguitargadgets.com/diagrams/cssussc.gif

but don't expect much from either of these circuits, there's plenty of better designs out there IMO

-Jeremy

[petemoore]

ANyone try or have thought on the Craig A. Comp ?
 The Three OA's and a Vactrol one...

[Joe Kramer]

ANyone try or have thought on the Craig A. Comp ?
 The Three OA's and a Vactrol one...

Hi!

I like the Anderton comp, but it's less "sustainy" and more "limity."  A trick I've done, and have seen others do with that circuit, is to add more gain at the input of it (another op amp) and get more sustain.  But then the sound can get uneven.   Thomas Henry at Midwest Analog has an opto-comp design that I've been curious about, but you'd have to buy his kit.  Wish I knew what  he's doing in that circuit, and how it differs from the Anderton version.

Joe

[Paul Perry (Frostwave)]

Looking at the colorsound circuit referred to above, I just can't iumagine how anyone could have come up with exactly that design!!!
(unless they were modding a fuzz, perhaps..)

[rubberlips]

I tried a sustain unit I copied years ago which was a combination of the anderton and the black box from what I can figure. It had no controls, had an LED/LDR arrangement over an opamp and definately sustained the note - a bit of feedback was also helpful. But oscillated as soon as you turned the volume down on the guitar. I'll post it one day when I draw i up - someone will probably recognise the circuit.

but don't expect much from either of these circuits, there's plenty of better designs out there IMO

Jay what other designs do you find better??

Cheers

Pete

[SolderBoy]

Thanks for the info guys.  The commercial opto-compressors I've tried have all had too slow an attack.  I'm a bass player, and I want one that I can kick in when I slap.  So I guess I need something that is more "limity" than "sustainy" - fast attack, medium fast release.  I've used a few fancy ones in studios that sound great.  Even used a x-over and two different compressors for hi and low on ocassion.

The black-box circuit caught my eye because it looked so simple - fun to mess around with on the breadboard.  

http://www.geofex.com/FX_images/rolandsu.gif

This one, from R.G's site looks similar too.

Maybe I'd be better off with a compressor that is controlled by a fet, or perhaps one that has a transconductance opamp...

[rubberlips]

maybe breadboard a few up and see how they sound for bass. I'm looking for a compressor for bass as well to add to a preamp, but I'll try a few first to see how universal they are.
I'm building an orange squeezer tomorrow which I should have done by the morning to see how it sound.

Pete

[Peter Snow]

...Thomas Henry at Midwest Analog has an opto-comp design that I've been curious about, but you'd have to buy his kit. Wish I knew what he's doing in that circuit, and how it differs from the Anderton version.

It's very similar to Anderton's compressor except that Tom Henry's version has a neat little tone control inserted just before the final opamp.  It uses a CLM-600(0) opto-coupler, 1 dual and 1 single opamp plus a few caps and resistors.

I haven't built it, but knowing Tom Henry's other designs it probably works very well.

Peter

[SolderBoy]

I also have a few circuits from those little babini books also.  One is similar to the anderton, and the other uses half a 13700 - sorta like the ross/dyna.