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, available as a 500 series module or in single/dual channel 19" rackmount configurations. It is directly inspired by the API 312, a preamp used widely in 1970s recording consoles. Designed for clarity and punch, it’s especially favored for drums and percussion due to its fast transient response. The unit features a high-impedance DI input for instruments and is built with premium components, including Jensen transformers and the BAE 2015 opamp. Every unit is hand-wired with discrete electronics—no circuit boards—and uses gold-contact switches 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
The BAE 312A is built without capacitors in the audio path, contributing to its fast, punchy sound ideal for transients like drums. It uses Jensen input and output transformers and the BAE 2015 discrete opamp, with all circuitry hand-wired using discrete components—no printed circuit boards. The front panel includes switches for phase reverse, pad, and phantom power, with gold contacts for longevity. A remote power supply delivers four times the current needed, ensuring optimal performance. The design reflects BAE’s commitment to replicating high-end vintage preamp characteristics from the 1970s and earlier.
Context
The original API 312 microphone preamplifier was used in numerous recording consoles throughout the 1970s, forming the foundation for the 312A’s design. The 312A is part of BAE Audio’s 500 series lineup, with the 312B module offering the same sonic character but with an additional 5dB of pad.
Market
The manufacturer’s advertised price (MAP) for the 312A single mic pre with power supply is $1,100.00, and 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 priced at $860.00, the same as the 312B module.
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