BAE 312A

A hand-wired microphone preamp in 500 series or rackmount format, inspired by the classic API 312 design.

Overview

The BAE 312A is a microphone preamplifier made by BAE Audio. It comes as a 500 series module or in single or dual channel 19" rackmount versions. It is directly inspired by the API 312, a preamp used widely in 1970s recording consoles. It is built for clarity and punch, and its fast transient response makes it a favorite for drums and percussion. There is a high-impedance DI input for instruments. The parts are top shelf, including Jensen transformers and the BAE 2015 opamp. Every unit is hand-wired with discrete electronics - no circuit boards - and the switches have gold contacts for durability.

Specifications

Frequency Response	5Hz to 75kHz (-3dB)
Gain	10 to 66 dB
Equivalent Input Noise	-120 dBu; Unweighted 300kHz Bandwidth
Maximum Output Level	+27.1 dBu @ 600Ω
Common Mode Rejection Ratio	110dB min @ 60Hz
Mic Input Impedance	≈1400 ohms
Line Input Impedance	10k ohms
DI Input Impedance	≈250k ohms
Output Impedance	75 ohms
Power Requirements (Rackmount)	115/230 VAC, 27W
Power Requirements (Module)	40mA per Rail
Weight (Module)	1 LBS / 0.45 KG
Weight (Single Rackmount)	7 LBS / 3.18 KG
Weight (Dual Rackmount)	8 LBS / 3.63 KG
Dimensions in Inches (Rackmount)	19W x 1.75L x 9D
Dimensions in Inches (Module)	1.5W x 5.5L x 6D
Inputs/Outputs	XLR connectors on the back for mic input and output and phone jack in front for direct input; 1/4" Hi-Z instrument input

Design

There are no capacitors in the audio path of the BAE 312A. That gives it the fast, punchy sound that suits transients like drums. It uses Jensen input and output transformers and the BAE 2015 discrete opamp. All the circuitry is hand-wired from discrete components, with no printed circuit boards. The front panel has switches for phase reverse, pad and phantom power, again with gold contacts for longevity. A remote power supply delivers four times the current the unit needs. BAE aimed to replicate the character of high-end vintage preamps from the 1970s and earlier.

Context

The original API 312 microphone preamplifier was used in numerous recording consoles throughout the 1970s, and the 312A's design builds on it. The 312A is part of BAE Audio's 500 series lineup. The 312B module has the same sonic character but adds 5dB of pad.

Market

The manufacturer's advertised price (MAP) for the 312A single mic pre with power supply is $1,100.00. A pair with power supply is $2,090.00. Without power supply, the single unit is $880.00 and the pair is $1,870.00. The 500 series module version is $860.00, the same as the 312B module.