The Heritage Audio 8173 Microphone Preamplifier Module is a hybrid 80 series console-compatible module that combines an 80 dB microphone and 10 dB line recording preamplifier with a 4-band EQ based on the vintage 1081 module designed by Rupert Neve. The module was designed so that a recording engineer could use the flexibility of the full spectrum 1081 EQ with the sound of the 1073's Class A amplification. This module features the same Class A circuitry, the same specifications, and the same construction techniques used in the original 1073.
The unit supports selectable HI-LO minimum balanced and floating input impedances that accommodate a range of microphone types including vintage ribbons. It includes a ±16 dB selectable low-frequency Baxandall shelving EQ at 35 Hz, 60 Hz, 110 Hz, and 220 Hz. For lower middle frequencies, the unit includes a 1081 inductor-based ±18 dB peaking fixed 'Q' equalizer with center frequencies at 220 Hz, 270 Hz, 330 Hz, 390 Hz, 470 Hz, 560 Hz, 680 Hz, 820 Hz, 1000 Hz, and 1200 Hz. For upper middle frequencies, the unit includes a 1081 inductor-based ±18 dB peaking fixed 'Q' equalizer with center frequencies at 1500 Hz, 1800 Hz, 2200 Hz, 2700 Hz, 3300 Hz, 3900 Hz, 4700 Hz, 5600 Hz, 6800 Hz, and 8200 Hz.
An 18 dB per octave slope inductor-based high pass filter push-button switch allows you to cut below 50 Hz, 80 Hz, or 300 Hz depending on the application. An EQ button allows for the equalizer to be turned on or off and a phase button allows you to flip the signal 180°.