500 Series Wiki
Heritage Audio 73 JR

Heritage Audio ´73 JR is a pre-amp for the 500 series, manufactured by Heritage Audio.

History[]

The Heritage Audio ´73 JR was released in 2013.[1]

Official description[]

Following his successful big brother, the 1073/500, the new ´73JR is a 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 ’73 junior is a faithful 3 stage all class A 1073 preamp. Styroflex and tantalum capacitors have been used throughout. No corners were cut.

A useful all discrete class A hi pass filter has been added, essential for recording everything with the exception of probably kick drum and and bass.

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.

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 lunchbox PSU healthier and makes the 73JR independent of the rest of the slots.

  • 80dB Class A Microphone preamplifier, HI-LO selectable minimum input impedance, balanced and floating. High gain positions show a higher impedance, ideal for old ribbon mics.
  • 50Db Class A Line preamplifier, bridging input impedance, balanced and floating.
  • All discrete Class A Ultra High Impedance J-Fet Direct Input on a high quality Neutrik Jack. The DI circuit is ahead of the Mic Input transformer, so the transformer is ON when in DI mode. DI is automatically switched on when inserting a jack.
  • Class A single ended, 2N3055 driven, high headroom output stage.
  • PAD: 20dB Mic input attenuation ahead of the input transformer to avoid overloading it.
  • HI PASS FILTER: Active all discrete Class A 3rd order Bessel, 80Hz Hi Pass Filter. 18dB/octave slope.
  • OUTPUT control to allow overloading of the preamp.
  • Internal slow turn-on +24v power supply for lower inrush current, which improves your lunchbox performance.
  • Carnhill Input and Output transformers.
  • 3 gain stage, genuine modular card construction. All active circuitry is on pluggable cards for easier service.
  • Marconi style knobs and vintage style engraved pushbuttons.

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