Maxon CP101 IC chip?

[AC30Dirty]

Hey guys, I just bought a pack of ten TL072CP IC's on eaby for $2.00 Anyway i was looking inside my maxon CP101 compressor (just curious really) and saw that it had a JRC4558DD chip in it. Would replaceing the chip with the TL072 improve the tone at all? I originally bought the chips for my re-issue Deluxe memory man but since i have chips left over might as well...  Also, can u use these chips in a BOSS SUPERCHORUS as well? Thanks

[Unbeliever]

'Tone' is subjective, but the swap might improve the noise performance somewhat. Myself, I prefer the 4558 over the TL072 in the audio stages of most phasers I've built up. I'll hate myself later for this - the 4558s sound 'warmer' to my ears in this application.

Try it and see!

[Mark Hammer]

Depends where the chip is used.  There will be an audio and a nonaudio path in the compressor.  Generally, "lesser" op-amps will be used in the nonaudio path because noise is irrelevant there.  My guess is that if there is one of each in the pedal (TL072 and 4558), the 4558 is in the sidechain/rectifier path for deriving the envelope signal used to control the amount of gain reduction in the audio path.

Bottom line: don't bother unless you are desparate for a 4558 somewhere else and can't find any.

[AC30Dirty]

Thanks for the feedback guys. The pedal only has one IC chip (the JRC4558DD). But, your probably right Mark; I guess I should just leave things the way they are.