Heritage Audio 81A Elite - '73 Mic Preamp with '81 Equaliser

Heritage Audio 81A Elite - '73 Mic Preamp with '81 Equaliser

The Heritage Audio 81A is a 1073 mic preamp and 4 equaliser. The HA-81A’s preamp section is an 80 dB, all discrete Class-A design with Carnhill/St. Ives input and output transformers, exactly the same one found in the other Elite Series modules. The preamp features gain, output trim, -20db pad, polarity reverse, and +48v phantom power.

The HA-81’s equalizer section is an exceptionally musical 4 band, inductor-based equalizer with high and low pass filters. Where 3 band equalizers such as the typical 73-style exceed at musicality but may get short of features, the HA-81A EQ equally excels on both. Extreme control over Shelf or Bell response curves on the high and lows, dual Q on both mid bands, with dedicated high and low mid ones, and a range of 40 frequency selections to choose from.

Specifications

• Microphone input impedance: HI, 1200 Ohm minimum, LO, 300 Ohm minimum. Higher gain positions gradually have greater impedances, optimum for low gain ribbon mics. Input is transformer balanced and floating.
• Line input impedance: 10KOhms bridging, transformer balanced and floating.
• Output impedance: Less than 75 Ohms, transformer balanced and floating, to drive a load of 600 Ohms.
• Maximum output: Greater than +26.5dBu into 600 Ohms (internally terminated)
• THD: Less than 0.025% at 1Khz, Less than 0.05% at 100Hz.
• Frequency response: 20Hz (+0.3dB) to 20Khz (-0.2dB).EQ Off. For EQ ON frequency response please check the features section.
• Maximum Gain: Slightly greater than 80dB.
• Equivalent Input Noise: Less than -125dBu at 80dB mic gain.
• Output stage noise: Less than -100dBu.
• Power consumption: Less than 150 mA @48VDC.