Fostex 3070 Compressor - Mod ?

[aleaney]

Have any of you ever tried to mod this compressor? Mine doesn't seem to do too much, it's pretty subtle and the LEDs don't seem to work, the gate sounds terrible and is useless. Any recommended Burr Brown upgrades perhaps?

I took it apart and found a bunch of ICs and Opamps, here's the list:

U1: 072DF JRC 5082
U5: 072D JRC 5055
U4: 072D JRC 5055
U8: 4558D JRC 5200
U3: 4558D JRC 5200
U6: 072DF JRC 5082
U12: MC14069UB CP J8534
U11: TC4016BP
U9: 4558D JRC 5200
U2: 4560DX JRC 5015
U7: 072D JRC 5055
U13: IR2431 SHarp 258A

here's some photos sorry about the terrible quality!

 

[Proaudioman]

Hello mate I am new to this forum I found the info you posted on google I have also looked into moding the unit mine arrived without the pot in attack position I have been trying to find a schematic with no luck apart from purchasing for $35 I only paid 99p so not keen on spending alot for manual. Would you be able to look at the pot to identify what it's resistance and taper is for me many thanks.

 

[Proaudioman]

Moding 3070

With regard to modding the unit I was looking at replacing the op amps on the audio in and output either the 072D's or 4558's I have successfully done this with very good result with other units of similar type. My drop in replacement is the OPA2134 for 072D and OPA2604 for the 4558's but it does depend on your final use. I think there may be other options too that until mine is working I have not looked into.