Behringer 1273 Dual Channel Microphone Preamplifier

Behringer 1273 is a dual-channel microphone preamplifier designed for studio recording and professional audio environments. It enables microphone, line, and instrument signal amplification with integrated equalization for engineers and producers, supporting analog recording and mixing workflows. This makes it ideal for tracking and processing sources where transformer-based signal handling and tonal control are critical.

The unit operates using Class A discrete circuitry with transformer-balanced inputs and outputs on each channel. Input selection, gain staging, impedance behavior, and signal routing are controlled through front-panel switches and stepped gain controls. Equalization is applied through inductor-based filters and selectable frequency bands.

This configuration supports precise signal capture, tonal shaping, and integration into studio signal chains. It can be used for recording vocals, instruments, and line-level sources in rack-mounted systems. The device operates with an internal universal power supply for global use.

Key Features

• Dual Channel Design: Two independent microphone preamplifier channels with equalization
• Class A Circuitry: All discrete signal path for consistent analog performance
• Midas Transformers: Custom-built input and output transformers on each channel
• Stepped Gain Control: Electronically controlled resistor-stepped rotary gain switch
• Inductor Based EQ: Three-band equalizer with selectable frequency points
• Comprehensive Switching: Dedicated phase tone insert line instrument and phantom power controls per channel

Technical Specifications

Audio Inputs - Microphone
Type: 2 x XLR, transformer balanced front, 2 x XLR, transformer balanced rear
Impedance: 300 Ω / 1200 Ω, balanced
Max. input level: +19 dBu
Gain: -20 to 80 dB
Mic EIN @ 80 dB gain, 22 Hz to 22 kHz: -125 dBu unweighted
CMRR @ 60 dB gain: > 90 dB

Audio Inputs - Line
Type: 2 x 1/4 inch TRS in combi socket, transformer balanced front, 2 x 1/4 inch TRS, transformer balanced rear
Impedance: 10 kΩ, balanced
Max. input level: +30 dBu attenuated -34 dB
Gain: -20 to 80 dB
CMRR @ 0 dB gain: > 80 dB

Audio Inputs - Instrument
Type: 2 x 1/4 inch TRS, front, hi-Z via transformer
Impedance: 600 kΩ, unbalanced
Max. input level: +30 dBu attenuated -20 dB
Gain: -20 to 80 dB
Insert return: 2 x 1/4 inch TS

Audio Outputs
Type: 2 x XLR, 1/4 inch TRS, transformer balanced
Impedance: < 80 Ω balanced
Max. output level: +28 dBu
Insert send: 2 x 1/4 inch TS

System Specifications
Frequency response microphone: 20 Hz to 20 kHz, ±0.5 dB
Frequency response line and instrument: 20 Hz to 20 kHz, ±1 dB
Distortion THD+N: <0.01% @ 1 kHz, +4 dBu
Distortion THD+N: <0.07% 50 Hz to 20 kHz, +4 dBu
Noise: < -83 dBu 20 Hz to 20 kHz unweighted
Dynamic range: > 102 dB typical 20 Hz to 20 kHz unweighted
Circuit: Class-A amplifiers, inductor based EQ

EQ Section
Hi pass filter: 50 / 80 / 160 / 300 Hz, 18 dB per octave
Low-band frequency range: 35 / 60 / 110 / 220 Hz
Boost / cut: ±15 dB
Mid-band frequency range: 360 / 700 / 1600 / 3200 / 4800 / 7200 Hz
Boost / cut: ±15 dB
High-band frequency range: 10 / 12 / 16 kHz
Boost / cut: ±15 dB

Controls
Buttons: 2 x 48 V phantom power, 2 x polarity invert, 2 x tone, 2 x line, 2 x insert, 2 x instrument, 2 x EQ in
Gain controls: 2 x gain -20 to 80 dB
EQ controls: 2 x low ±15 dB, 2 x mid ±15 dB, 2 x high ±15 dB
Hi pass controls: off, 50 Hz, 80 Hz, 160 Hz, 300 Hz
Output level: zero off to 0 dB
Power switch: On off