Heritage Audio 73 EQ JR 500 Series Equalizer and Line Preamp

Heritage Audio 73 EQ JR: The Classic Console EQ in a Slot

The Heritage Audio 73 EQ JR is a single-slot 500 series equalizer and line preamp, delivering the three-band inductor EQ and transformer-coupled line stage of the classic British console channel. It is the EQ companion to the 73 JR preamp, letting you build a complete channel across two 500 series slots. Genuine inductors and a Class A transformer-balanced output keep the curves and tone authentic. In one slot it brings a legendary equalizer to any modular rack.

What This Module Does

The 73 EQ JR is an equalizer with a built-in line preamplifier, designed to shape line-level signals rather than amplify a microphone. You feed it a line source, or the output of a preamp, and it tailors the balance of lows, mids, and highs. The onboard line preamp sets level so heavy EQ boosts do not overload the next stage. Pairing it with a 73 JR gives you a full mic preamp and EQ channel in the 500 format.

A Three-Band Inductor Equalizer

The EQ offers low shelving, an inductor-based midrange peak, and high shelving, the classic three-band console layout. A shelving band lifts or cuts everything past its frequency, while the midrange peak focuses on a chosen center. The midrange uses a dual inductor with a fixed Q and selectable centers, the design that gives the classic console its musical mids. These curves add air, presence, or body without harshness.

Selectable Frequencies Across the Bands

The high band shelves at 10, 12, 16, or 20 kHz, adding air or taming brightness. The low band shelves at 35, 60, 110, or 220 Hz for weight or a cleaner bottom end. The midrange peak steps across 0.36, 0.7, 1.6, 3.2, 4.8, and 7.2 kHz at up to +/-18 dB. Switched frequencies make settings easy to recall from track to track.

The Line Preamp and Its Range

A transformer-coupled line preamplifier sits ahead of the EQ with a range of +6 to -20 dB. That range lets you apply heavy EQ boosts and still trim the level so the signal never overloads an A/D converter. The line stage also adds the transformer character of the console channel. It is what makes the module a useful processor and not just a passive EQ.

Class A Output and EQ Bypass

The 73 EQ JR uses the same Class A transformer-balanced output stage found in the classic console channel, driving the signal with authentic tone. An EQL button switches the equalizer section in and out, so you can compare the processed and clean signal instantly. That makes it easy to judge how much shaping a track really needs. The output is built to feed a converter or the next module cleanly.

Power Built for the Rack

The module runs on an internal 24V slow turn-on power supply, which limits inrush current when the rack powers up. That protects the enclosure's supply and keeps the module's behavior consistent. Deriving a true 24V rail also preserves the intended tone of the circuit. It is a design aimed at both reliability and sound.

Where the 73 EQ JR Fits Your Studio

Engineers pair the 73 EQ JR with a 73 JR preamp to build a full British console channel in a 500 series rack. On its own it shapes line signals, stems, and mix bus sources with classic console curves. Its selectable frequencies make it easy to dial repeatable tones across a session. As the console EQ in a single slot, it completes a modular signal chain.