Alesis 3630 Mod

PSU MoD: - Get a 9vac (1000ma or greater) power supply to replace the stock wall wart (absolutely nessasary)
- If 1n400x diodes are not used in the rectifier, then replace and put in 1n400x's
- Replace c2 & c3 (1000uf 16v caps) with 1800uf 16v panasonic caps (EEU-FR1C182LB)
- Replace c4 & c5 (1000uf 25v caps) with 1800uf 25v panasonic caps (EEU-FR1E182)
- Add .1uf film caps across input and outputs to ground of the 7815 and 7915 regulators. (as stabalization) see figure 1
- Remove and Jumper s2 and s3 with wires to either +4(default) or -10 depending on your application. (Switches suck here)

IC MoD: - Replace u2,4,6 with MC33079, LME49740NA, OPA404, or OPA4227
- Replace u3, and u7 with that 2180AL08-U (lift pin 4, pin 4 should not connect to anything)

Capacitor/resistor MoD: - Replace R14 & 56 with 1k Metal film resistors
- Replace R12 & 54 with 100k Metal film resistors
- Replace R15, 41, 57, & 73 with 6.2k Metal film resistors
- Replace R26 & 68 with 470ohm Metal film resistors
- Replace R22 & 64 with 22k Metal film resistors
- Replace R23 & 65 with 20k Metal film resistors
- Replace C11, 16, 29, & 33 with 22uf 35v bipolar panasonic caps (ECE-A1VN220U)
- Bypass those caps with .22u film caps
- Place some foil tape over the switch hole. Screw into the foil/case in a spot that won't contact any parts or the board. (to make electrical contact).

When all these mods are done, you are left with a very usable and good sounding compressor. It will have a lowered noise floor and better bass response.

Disclaimer: I encourage people to DIY and I'm here in a informative role.


ModDefecation is about making equipment sound better, providing knowledge and support, repairing that awesome piece of gear, and custom builds. Send me you questions or Ideas.