Heritage Audio Improves 500 Series 73-style mic Pre-Amp with 73JR II

  • By: Thorsten Meyer
  • Date: Monday, 14 December 2020
  • Time to read: 3 min.

3JRII The 2021 Update

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. European pro audio manufacturer Heritage Audio announced the availability of the 73JR II — advancing its already classic 73JR single-slot 500 Series true 73-style mic preamp module with additional features surely set to satisfy the most demanding of recording engineers.

  • 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.

Compromises can be made when trying to adapt a 73-style mic preamp into the smaller 500 Series format fit for compact enclosures — such as API’s popular ‘Lunchbox’ (letting space-restricted discerning users choose to house however many modules they wish from a seemingly-endless selection of manufacturers) or, of course, Heritage Audio’s own OST range of 500 Series enclosures— but this is far from the case with Heritage Audio’s 73JR II. By boasting heritage quality through and through, it uses only discrete, through-hole traditional components combined with hand labour to create a great-sounding Seventies-vintage vibe. As a faithful three- stage, all Class-A 73-style preamp, it is the real deal, with Styroflex and tantalum capacitors used throughout, and no corners cut.

Heritage Audio 73 JR mkII 34 Left
Heritage Audio Improves 500 Series 73-style mic Pre-Amp with 73JR II 7

Indeed, it uses the full three-gain stage circuit for up to 80 dB of gain with noise of -125dBu EIN (Equivalent Input Noise) over all the gain positions, and a true 24v onboard power supply for identical performance and distortion point. The output transformer is a custom Carnhill, manufactured for Heritage Audio by the renowned British company concerned in its St Ives factory in Cambridgeshire, while the input transformer is another custom Carnhill, this time manufactured in Oxfordshire — the same one found in Heritage Audio’s higher-end 80 Series modules, in fact, so hugely impacts the musical mojo of the 73JR II as a direct result.

73JRII FEATURES
Heritage Audio Improves 500 Series 73-style mic Pre-Amp with 73JR II 8

Readily saying all that, then, the 73JR II itself is an update to Heritage Audio’s already classic 73JR single-slot 500 Series true 73-style mic preamp module with added features surely set to satisfy the most demanding of recording engineers. Enter an all-discrete Class-A hi-pass filter, sweepable from 20 to 220 Hz — making it easier to tighten the low end without affecting desired frequencies; a LINE mode, allowing for reamping of prerecorded tracks — perfect for adding some color to lifeless recordings; and a D.I. (Direct Input) — itself automatically switching to DI mode when inserting a 1⁄4” TS cable — that is an all-discrete Class-A JFET circuit fronting the microphone transformer to provide all the color and weight anyone could conceivably ask for!

Finally, Heritage Audio has paid particular attention to power handling by implementing internal +24v slow-turn-on-regulation — hugely healthy for any 500 Series enclosure’s power supply since it keeps the 73JR II’s power independent from other slots.

Simply speaking, anyone adding a 73JR II to their 500 Series recording setup is assured of a real deal 73-style sound. 

About Heritage Audio

Heritage Audio was founded in 2011 by Peter Rodriguez a Sound Engineer and Musical Producer with vast experience in the Music Industry. Heritage Audio’s mission is to bring back the Golden Age of Recording and adapting it to the 21st Century Studios. Heritage products cover the various needs in analog signal processing. They are designed and manufactured in Spain and they are sold in more than 36 countries worldwide.

Pricing and Availability

The 73JR II is shipping and available now via RAD Distribution in the US— with a MAP (Minimum Advertised Price) of $949.00 USD — and elsewhere — with an SSP (Standalone Selling Price) of €949.00 EUR (excluding VAT) — via Heritage Audio’s growing global network of dealers.

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