DOD 280 Compressor mods !!!

[JasonG]

I just scored a mid 90's Dod 280 compresser and want .
1 Less noise,
2 faster attack
Are there any opamp suggestions? Would it be worth switching out the resisters for precision resisters?
Thanks for any help!

[Mark Hammer]

Judging from the 280 schematic I have in front of me...

1) You have just about the fastest attack that the VTL5C2 is capable of (i.e., the attack is set by the photocell properties, not the electronics feeding it, which means no mods other than moving to a faster LDR).  The 47uf cap to ground sets the recovery/decay time, which CAN have an effect on what seems like the attack time.  Consider sticking a 22uf or 33uf in there in its place, though be prepared for some ripple if the decay time is too fast.

2) The resistors that MIGHT affect noise levels likely have much less influence than the input signal quality, when it comes to noise.  It is possible that the op-amp, if replaced with a lower noise unit (e.g., NE5532 or OP2134, or TL072) might improve matters.

[JasonG]

Cool thanks Mark ! I apreciate the advice.