Heritage Audio DMA-73 Dual Mic Preamp

The Heritage Audio DMA73 is a true dual 1073 style mic preamp in a 1 rack unit format. It has some added key features that will cover all the recording needs for engineers and musicians that don't find the need to track with EQ.

Employing only discrete circuitry and conventional components, the DMA73 is a faithful 3-stage all class-A 1073 preamp. Styroflex and tantalum capacitors have been used throughout - no corners cut here.

A useful all-discrete class-A hi pass filter has been added; an essential tool for recording everything from vocals to instruments and more (with the exception of kick drum and bass).

The Line mode allows for reamping of prerecorded tracks and is perfect for adding some class A colour to lifeless recordings.

The DI circuit is an all discrete class A JFET circuit ahead of the MIC transformer, so all the juice is there. Since its introduction in 2012, it has become a classic DI for bass.

Power handling has been addressed by means of an external linear power supply, which is included in the package.

Features/Controls
Input Gain Switch - 5dB steps from 30 to 80
Mic Input Impedance - 1200Ω, 300Ω when pressed
Phantom Power Switch - Phantom power on/off
Output Attenuator - Attenuate from 0 to -inf
D.I. Input & Thru - High impedance JFET
Line Push Button - Switches from mic/DI to Line
Mic Pad Push Button - 20dB pad, ahead of the input transformer
Phase Push Button - Flips the phase 180 degrees
High Pass Filter - -3dB at 82Hz, discrete class A

Specifications
Microphone input impedance: HI, 1200 Ohm minimum, LO, 300 Ohm minimum. Higher gain positions gradually have greater impedances, optimum for lo gain ribbon mics. Input is Carnhill transformer balanced and floating.
Line input impedance: 10K Ohms bridging, Carnhill transformer balanced and floating.
DI input impedance: Greater than 2 Megohms, unbalanced.
Output impedance: Less than 75 Ohms, Carnhill transformer balanced and floating, to drive a load of 600 ohms (factory terminated).
Maximum output: Greater than +26dBm into 600 ohms.
THD: Less than 0.025% at 1 Khz, less than 0.05% at 100Hz.
Frequency response: 20Hz ( +0.3dB ) to 20Khz (-0.2dB)
Maximum gain: Slightly greater than 80dB
Noise: Less than -100dBm.
Power consumption: 88 mA per rail @+-16VDC.
Size: 1RU