CAPI VP312

CAPI VP312 is a pre-amp for the 500 series, manufactured by CAPI.

Official description
Classic Audio VP312

The VP312 is a clone of the vintage API 312 mic preamp. It is about as close to the original 312 as you can get right now, and at this price it is seriously unbeatable. You won't find any compromises in quality either. As with all of the equipment from CAPI the VP312 has custom Ed Anderson transformers and top quality components throughout.

The VP312 only has two minor differences from the original 312 circuit (which can be left off if desired). Here's Jeff's explanation...

From CAPI-gear.com:

There are only two main differences in the audio path between a vintage 312 card and the VP312. The first difference is the allocation on the board for a loading resistor, R2. This is often referred to as the Load R and is used in many of the mic preamp circuits including the VP25 and VP26 preamps. The input transformer you use will really dictate whether or not you use this Load R as it is optional and not required. With the EA2622, the circuit sounds great both with and without it. This Load R was typically not found on a stock API 312 card. The second difference is R12 which immediately follows the discrete opamp’s output. I use a zero ohm or jumper resistor for R12. I have utilized this R12 for two reasons. The first is as a little protection for the remaining circuit if there is some sort of rare DOA failure. Hopefully R12 will smoke before any other damage occurs. The second reason is merrily to “jump” over a few PCB traces. I really don’t think it degrades the sound using a zero ohm resistor. A hard wire jumper could also be used.

Features


 * 60dB of gain provided by a 2520 style opamp, I regularily stock the GAR2520, GAR1731, and the SL2520 Red Dot.
 * -20dB Pad switch, polarity switch, and mute switch.
 * Fast drain 48V Phantom power.
 * Output attenuator which allows you to drive the opamp and 2503 output transformer HARD and attenuate back down to digital safe levels (this is something rarely implemented on API style preamps, and makes for a huge variety of tones).