Buzz Audio Essence Stereo Pair

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This listing is for a stereo pair.

You Will Receive

  • Buzz Audio Essence (2)
  • Sequentially Numbered Pair

control genius

You may know the sound of vintage optical compressors like the Teletronix LA2A, but often you need more control than just 2 knobs. So we present an ehanced design - the Essence - with attack & release settings carefully selected for a more varied dynamic palette plus the intelligent auto modes for that really smooth "set and forget" operation we all love. And unlike the slow LA designs, this compressor can also respond much faster when you need it. The soft knee opto action is perfect for smoothing the dynamics of vocals and a stereo pair will find immediate use to glue together stems, synths and the mix buss. And as our users report, the Essence is brilliant on bass guitar!

audio path quality

The audio input is coupled directly to our custom made LDR (light dependant resistor) gain reduction element via a Lundahl LL1540 input transformer. This is followed by a discrete signal path using our Class-a BE40 amplifier and BE50 high current line driver that excites the Lundahl LL1517 output transformer. The combination of high end Lundahl transformers with our circuits creates a very warm low end sound along with a creamy top end finish void of midrange harshness.

creative versatility

The Essence is the only 500 series compressor (that we know of) to feature a side chain insert point so you can apply equalisation to the compression characteristic to control certain parts of the audio spectrum. The insert can also be used to "key" the compressor from another sound for all sorts of creative pumping effects. In addition, there is on board side chain shelving eq allowing you to quickly adjust the compressor sensitivity at high and low frequencies.

For critical stereo operation we recommend you order a factory matched pair.


  • GAIN - sets the output gain from 0dB to +15dB.
  • DRIVE - sets the amount of compression applied to the signal, clockwise rotation means more compression.
  • ATTACK - 4 position switch with attack time settings of 1mS, 15mS, 70mS and our excellent Auto mode.
  • RELEASE - 6 position switch with recovery time settings of 100mS, 200mS, 400mS, 800mS, 1600mS and the intelligent Auto mode..
  • RATIO - 4 position switch sets the depth of compression from light to heavy, 2:1, 5:1, 10:1, 20:1 all with the soft knee action. 
  • METER - can be switched to read input level, output level and gain reduction. A jumper on the PCB is used to set the peak level reference from +4dBu or +14dBu.
  • BYPASS - toggle switch used to hard wire bypass the essence.
  • S.C. MON - allows you to hear the side chain signal (the side chain eq) and the side chain insert return signal.
  • S.C. HI EQ - applies 8dB at 10kHz of boost or cut to the side chain signal and therefore to the compression.
  • S.C. LO EQ - applies 8dB at 100Hz of boost or cut to the side chain signal and therefore to the compression.
  • LINK - using the 500 frame link system, two Essences can be linked for stereo operation.
  • S.C. INS - this switch engages the side chain insert point which are the input/output connectors associated with the second slot the Essence uses.


  • Frequency Response with no gain reduction; 14Hz to 107kHz, +/- 1.5dB
  • Maximum Input Level; +25dBu 
  • Maximum Output Level; +27dBu 
  • Side chain Max Input/Output Levels;+22dBu 
  • Total Harmonic Distortion
  • Measured at 0dBu input, no gain reduction, make up Gain 0dB; 100Hz = 0.1%, 1kHz = 0.015%, 10kHz = 0.002%
  • Measured at +10dBu input, 20dB gain reduction, make up Gain +15dB, Attack AUTO, Release 16; 100Hz 0.1%, 1kHz = 0.015%, 10kHz = 0.005% 
  • Residual Noise; -95dB A wtg, 150ohm source Z, make up Gain 0dB 
  • Make up Gain Range; 0dB to +15dB 
  • Maximum Available Gain Reduction = 25dB 
  • S/C HI EQ Boost/Cut; 8dB @ 10kHz
  • S/C LO EQ Boost/Cut; 8dB @ 100Hz 
  • Main Audio Input Impedance; 20k ohms, bal or unbal 
  • Main Output Impedance; 100 ohms bal or unbal 
  • Sidechain Send Output Impedance; 100 ohms unbal 
  • Sidechain Return Input Impedance; 44k ohms bal or unbal 
  • Size; (3"Wx5.25"H). Fits 2 spaces in API* 500VPR Series rack format 
  • Power requirements; 120mA +/- 15-18 volts DC, as supplied by rack power supply

Our ONE WITH EVERYTHING ZEN WARRANTY extends the standard manufacturer warranty by one year, see our ZEN WARRANTY page for details.