DBX 166 Mods
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These Mods clean up this compressor a lot and turn it from a standard piece of rack gear in to a decent piece of studio gear.
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PSU MoD: - Replace c3 ,c4, c7, and c8 with 1000uf-2200uf 35v caps
- Replace c5 and c9 with a .1uf film cap (preferably polypropelene)
- Bypass c6 and c10 with .1uf film caps _______________________________________________________________________________________________________________________________________________
Channel 1:

IC MoD: - Replace chip OA1 with better ic (NE5532, OPA2132, opa2134, OPA2107, LT1358, or LME49860NA (My fav)) and install a gold plated ic socket.
- Repalce chip OA2 with better ic (LME49710NA, OPA134, OPA602, opa627, or LT1357) and install a gold plated ic socket.
- Replace the VCA IC1 with a THAT 2180AL08-U (lift pin 4, pin 4 should not connect to anything)
- Add a 47pf NPO ceramic cap from pin 3 of OA2 to ground (Suggested by Jim Williams)

Capacitor/resistor MoD:
- Replace c14 with a 22uf 35v bipolar cap
- Bypass that with a .22u film cap
- Note: c14 was originally a 3.3uf cap. You could fit in a film cap in there if you are carefull.
- Replace c25 with a 22uf 35v bipolar cap
- Bypass that with a .22u film cap

- Replace r17 and r18 with 22ohm metal film resistors
- Replace r1 and r4 with 1k metal film resistors
- Replace r3 and r6 with 7.5k metal film resistors
- Replace r2 and r5 with 10k metal film resistors
- Replace r7 and r13 with 2k metal film resistors

IC Control Voltage (Optional) MoD: Turns this compressor into a beast.
- Replace chips OA3, OA4, and OA5 with gold plated ic sockets and a better ic like a LT1124 or LME49860NA.

Peakstop switching MoD: Turns on and off the peakstop circuit.
- Drill a hole in the front plate about .25 inches diameter. Install and wire in a DPDT gold contact switch here. Lift one end of CR5 and CR6. Solder 2 wires. One to cr5 and one to cr6 and solder the other end of the wires to each center contact of the DPDT switch. Solder 2 more wires to the vacant holes of cr5 and cr6 and wire these to one side of the switch.
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Channel 2:

IC MoD: - Replace chip OA6 with better ic (NE5532, OPA2132, opa2134, OPA2107, LT1358, or LME49860NA (My fav)) and install a gold plated ic socket.
- Repalce chip OA7 with better ic (LME49710NA, OPA134, OPA602, opa627, or LT1357) and install a gold plated ic socket.
- Replace the VCA IC8 with a THAT 2180AL08-U (lift pin 4, pin 4 should not connect to anything)
- Add a 47pf NPO ceramic cap from pin 3 of OA2 to ground (Suggested by Jim Williams)

Capacitor/resistor MoD:
- Replace c14 with a 22uf 35v bipolar cap
- Bypass that with a .22u film cap
- Note: c14 was originally a 3.3uf cap. You could fit in a film cap in there if you are carefull.
- Replace c55 with a 22uf 35v bipolar cap
- Bypass that with a .22u film cap

- Replace r117 and r118 with 22ohm metal film resistors
- Replace r101 and r104 with 1k metal film resistors
- Replace r103 and r106 with 7.5k metal film resistors
- Replace r102 and r105 with 10k metal film resistors
- Replace r107 and r113 with 2k metal film resistors

IC Control Voltage (Optional) MoD: Turns this compressor into a beast.
- Replace chips OA8, OA9 and OA10 with gold plated ic socket and a better ic like a LT1124 or LME49860NA.

Peakstop switching MoD: Turns on and off the peakstop circuit.
- Drill a hole in the front plate about .25 inches diameter. Install and wire in a DPDT gold contact switch here. Lift one end of CR5 and CR6. Solder 2 wires. One to cr5 and one to cr6 and solder the other end of the wires to each center contact of the DPDT switch. Solder 2 more wires to the vacant holes of cr5 and cr6 and wire these to one side of the switch.
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Disclaimer: I encourage people to DIY and I'm here in a informative role.
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Here are some pictures from some mods.
HERE!!! https://www.facebook.com/media/set/?set=a.566612136765790.1073741835.478520652241606&type=1&l=ff1646c994

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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.