Heritage Audio 73JR II

Heritage Audio 73 Jr. II - this is a microphone preamp and DI with a built-in -20 dB Pad attenuator, microphone gain up to 80 dB, line signal up to 50 dB, and Highpass Filter.

73 Jr. II is a 500 series microphone preamp based on the legendary 1073 preamp. It is an updated version of the classic 73JR model with some additional features. Using a discrete circuit and traditional components, the 73 Jr. II is a precise three-stage Class A preamp with the ability to amplify up to 80 dB, with a noise level of -125 dBu. The fully discrete class A high-pass filter has been updated and can be set from 20 to 220 Hz, allowing for more expressive low frequencies without affecting the desired frequencies.

Line mode allows you to overdub previously recorded tracks and is great for adding colour to lifeless recordings. The intelligent, switchable D.I. automatically switches from MIC mode to D.I. mode when plugged into the 1/4” jack, is a fully discrete Class A JFET circuit before the MIC transformer.

Particular attention has been paid to power management, with internal regulation of slow +24 V power-up (approx. 20 seconds to reach full voltage). This allows the 73 Jr. II to be independent of the other slots and makes the power supply of the 500 series housing more stable. Carnhill transformers on the input and output stages add warmth and character to your sounds. The gain level and output level are independent, allowing for rich saturation without limiting your levels.

HA73jr2 Features

• Designed for 500 series based on the classic 73 module
• Microphone preamp with 20 dB attenuator
• Gain up to 80 dB for microphone input, 50 dB line preamp
• Fully discrete Class A circuitry
• DI module
• DI input circuit is before the input transformer
• Variable high-pass filter
• Separate input and output gain controls.

73JR 2 Specifications

• Microphone input impedance: HI=1200 Ω minimum, LO=300 Ω minimum. Higher gain positions gradually have greater impedances, perfect for lo gain ribbon mics
• Input is transformer balanced and floating
• Line input impedance: 10 kΩ bridging, transformer balanced and floating
• DI input impedance: Greater than 2 MΩ, unbalanced
• Output impedance: Less than 75 Ω, transformer balanced and floating, to drive a load of 600 Ω (factory terminated)
• Maximum output: Greater than +26 dBu into 600 Ω
• THD: Less than 0.025 % at 1 kHz, less than 0.05 % at 100 Hz
• Frequency response: 20 Hz (+0.3 dB) to 20 kHz (-0.2 dB)
• Maximum gain: Slightly greater than 80 dB
• Noise: Less than -125 dBu EIN
• Power consumption: 86 mA per rail ±16 V DC.