Budda Chakra Compressor  [schematic]

All about modern commercial stompbox circuits from Electro Harmonix over MXR, Boss and Ibanez into the nineties.

Budda Chakra Compressor  [schematic]

Postby johnnyg » 01 Nov 2015, 23:01

BCCjgFSB.jpg


First optical compressor I've used and a nice change from DynaComp type I've only previously experienced. Also first attempt at publishing a full circuit trace; hopefully it's right.

BuddhaComp.pdf
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Re: Budda Chakra Compressor

Postby roseblood11 » 02 Nov 2015, 01:30

have you measured the LDR?
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Re: Budda Chakra Compressor

Postby johnnyg » 02 Nov 2015, 12:35

Dark resistance in circuit was c. 250k. But any other parameters (like on and off times) I've no idea. I would guess, like most circuits that use an optocoupler, one would have to plug in different types of LDR or vactrol to find something that works.

BTW the circuit reminded me of Rod Elliott's compressor designs and Rod provides some explanation of the circuit (like the 100uf cap across the LED: "some LDRs may give distortion at low frequencies. A 100uF cap in parallel with the LED will probably help if this is a problem").

http://sound.westhost.com/project92.htm
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Re: Budda Chakra Compressor

Postby dv8r601 » 08 Sep 2017, 20:49

I'm really on the hunt for a non ota comp and I want to build this one correctly. So, the 2w10 diode bridge has a max Vf of 1.1v, could I just sub that with rectifier diodes? Or do I just need to pony up and order one? I know what a bridge does and is I'm just curious if the diode type matter as much.
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Re: Budda Chakra Compressor

Postby bmxguitarsbmx » 09 Sep 2017, 03:33

Hey dv8r601,
In my estimation, this schematic is missing some connections.

Here is the link from above, that is now dead:
http://sound.whsites.net/project92.htm

Wish I could be more helpful, as it looks like it could be an interesting circuit.

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