The real 73 preamp sound – full gain, full transformers – in a single 500 Series slot. The Heritage Audio 73 JR II (HA73jr2) is the 2021 update of the 73 JR: a faithful 3-stage, all Class A 73-style mic preamp for engineers and musicians who track without EQ.
Why customers choose it
Who it is for
Home and pro studios building a 500 Series rack, vocalists, bass players and guitarists, and engineers who want a classic 73 mic preamp for vocals, drums and instruments.
What’s in the box
- 1 x Heritage Audio 73 JR II 500 series module
Specifications
| Format | 500 Series, single slot |
|---|---|
| Mic input impedance | HI 1200 ohm / LO 300 ohm minimum; transformer balanced and floating |
| Line input impedance | 10 kohm bridging, transformer balanced and floating |
| DI input impedance | Greater than 2 Mohm, unbalanced |
| Output impedance | Less than 75 ohm, transformer balanced and floating (600 ohm load) |
| Maximum output | Greater than +26 dBu into 600 ohm |
| Maximum gain | Slightly greater than 80 dB |
| Frequency response | 20 Hz (+0.3 dB) to 20 kHz (-0.2 dB) |
| THD | Less than 0.025 % at 1 kHz; less than 0.05 % at 100 Hz |
| Noise | Less than -125 dBu EIN |
| High-pass filter | Sweepable 20 – 220 Hz |
| Power consumption | 86 mA per rail at +/-16 V DC |
| Type | 500 Series microphone preamp |
| Transformers | Carnhill input and output |
| Circuit | Class A, discrete |
Good to know
- Needs a powered 500 Series rack, such as the Heritage Audio OST series.
- No EQ on this module; pair it with the Heritage Audio 73EQ JR for the classic 73 EQ.
- Higher gain positions raise the input impedance – good for low-output ribbon mics.
- It takes about 20 seconds to reach full voltage after power-on.
FAQ
Can I plug a bass or guitar directly in?
Yes. Plug a mono 1/4″ jack into the DI and it switches to DI mode automatically.
Is it the same as the original 73 JR?
It is the 2021 update, with a sweepable 20-220 Hz high-pass filter among the changes.
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