Heritage Audio HA73JR2 – '73 Junior API 500 Series Microphone Preamplifier Module

The 73JRII is the 2021 update to the already classic 73JR, a true 73 style mic preamp in a single 500 series slot with some added 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 73JRII is a faithful 3 stage all class A 73 preamp. Styroflex and tantalum capacitors have been used throughout. No corners were cut.

The useful all discrete class A hi pass filter has been updated, making it sweepable from 20 to 220 Hz. Now it is even easier to make your low end tighter without affecting desired frequencies.

The Line mode allows for reamping of prerecorded tracks and it´s perfect for adding some class A color to lifeless recordings.

The smart switched DI (automatically switches from MIC to DI mode when inserting a MONO ¼” jack) is an all discrete class A JFET circuit ahead of the MIC transformer, so all the juice is there. Since its introduction in 2013, it has become a classic DI for bass.

Finally, special care has been taken with power handling, implementing internal +24v slow turn on regulation (about 20 seconds to reach full voltage).This makes your 500 series enclosure´s power supply healthier and makes the 73JR independent of the rest of the slots.

• <> 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 transformer balanced and floating.
• <> Line input impedance: 10K Ohms bridging, transformer balanced and floating.
• <> DI input impedance: Greater than 2 Megohms, unbalanced.
• <> Output impedance: Less than 75 Ohms, transformer balanced and floating, to drive a load of 600 ohms (factory terminated).
• <> Maximum output: Greater than +26dBu 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 -125dBu EIN.
• <> Power consumption: 86 mA per rail @+-16VDC.