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Title: DOD 280 compressor
Post by: deucedriver on February 15, 2004, 10:03:05 AM

I'm looking for a way to slow down the onset of compression in this circuit. Any ideas would be appreciated. The schematic is at http://tonepad.com/getFileInfo.asp?id=40

Thanks
deucedriver

Title: DOD 280 compressor
Post by: Mark Hammer on February 16, 2004, 10:31:21 AM

The overall time constant (attack and decay) is set by the 47uf cap wedged between Q1 and Q2. Make it bigger and the response time will slow down.

Title: DOD 280 compressor
Post by: deucedriver on February 16, 2004, 11:48:11 AM

Thanks for the reply. Would changing the 4K7 resistor change the time constant or would it affect the photo resistor too much.

Cheers
Deucedriver

Title: DOD 280 compressor
Post by: Mark Hammer on February 16, 2004, 02:01:07 PM

From what I can tell, the resistor in question limits the current passing through the LED which, in turn alters its brightness and the response of the photocell. Best to leave it as is.

You MAY be able to stick in small value (<500R) resistors between the 47uf cap and the collectors of the two transistors that feed it, in order to alter charge-up time, but I'm just guessing here.

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DIY Stompboxes => Building your own stompbox => Topic started by: deucedriver on February 15, 2004, 10:03:05 AM