Heritage Audio's new Symph EQ is a stereo asymptotic analog equalizer

31 Jan 2021 by Lyubomir Dobrev | Approximate reading time: 2 Minutes

· Source: Heritage Audio

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Heritage Audio presents a modern take on the 70-year old Baxandall equalizer design with Symph EQ. Symph EQ is a master bus stereo asymptotic equalizer. It takes its name from the shape of its shelf curves – the boost or cut amplitude grows until the asymptotic value reached, resulting in controlled ultra highs and sub lows.

Heritage Audio Symph EQ

The Symph EQ started off as a functional equivalent to the Baxandall equalizer topology. It was introduced in 1952 by engineer Peter Baxandall as an inexpensive and clever approach to obtaining high and low shelf filters with boost and cut options in equalizers where parametric options are not required. Heritage Audio’s take results in a 1U-sized stereo rackmount unit with a “tight, sweet and natural” sound. The controls per channel are as follows:

High and low-pass filter: 15Hz to 160Hz or 10kHz to 30kHz, 12dB/octave filter.
Hi frequency controls: Frequency knob (8khz – 24kHz), Boost knob (0dB – 10.5dB), Cut button (turns the Boost knob into a Cut knob), +0.5dB button (turns the stepped 1dB increments Boost knob into a stepped 1.5dB increments Boost knob).
Lo frequency controls: Frequency knob (20Hz – 470Hz), Boost knob (0dB – 10.5dB), Cut button (turns the Boost knob into a Cut knob), +0.5dB button (turns the stepped 1dB increments Boost knob into a stepped 1.5dB increments Boost knob).

The center front panel includes an On/Off button, Bypass – Left and Bypass – Right buttons, and a M/S button for mid/side processing. The rear panel has dual inputs and dual outputs on balanced XLR connectors (unbalanced-compatible), along with a 5-pin power connector for the unit’s external power supply.

Build-wise, the Symph EQ has the same Carnhill input transformers as Heritage Audio’s Successor analog compressor. The outputs are driven by Class-A output amplifiers with Carnhill transformers, the same used across Heritage’s line of Neve 1073-style units.

: Heritage Audio Symph EQ front

: Heritage Audio Symph EQ rear

: Heritage Audio Symph EQ interior

Price and availability

The Symph EQ is available from Heritage Audio dealers such as Thomann at USD 1599. Would you be tempted to add this unit to your arsenal? Let us know in the comments below.