- As of May 1, 2017 -

Dual Mono, Pure Class A Parametric Music Equalizer

"The AD2055 is the best EQ I've ever heard. Having the cleanest low and low-mid frequencies, combined with the most open top-end makes this my favorite tool in the studio. I personally use five of these on all of my mixes." John G., CA

"The AD2055 in my opinion is the best stereo EQ on the market. Possibly the best ever made. I like it because it has a very natural, musical sound. Particularly noticeable are the clear open high frequencies and warm lows. I use it on whatever is most important in the mix. Sometimes it's the lead vocal, sometimes the mix buss itself. It has saved a lot of records." Rob C., CA

The AD2055 combines 100% discrete, pure class A signal amplifiers with state-of- the-art passive and active filter topologies. The AD2055's unique circuitry delivers very high resolution transient detail at the operational extremes of real world equalization demands. The AD2055 auto-bias DC servo loop control eliminates the need for all interstage capacitor coupling. The AD2055 breathes life into all musical performances!


  • Pure Class A, 100% discrete design

  • Smooth musical detail and sonic excellence

  • Minimum audio signal path

  • Dual mono operation

  • Transparent active and passive filter design

  • High headroom +30dB Very low noise -94dB

  • Fully balanced inputs and outputs

  • DC coupled, no transformers in audio path

  • Switched frequencies in high and low bands

  • Mid bands use X10 frequency for extended range

  • Wide bandwidth -3dB 1Hz to 450kHz

  • Low distortion less than 0.5% THD and IMD

  • All signal routing with sealed silver relays Conductive plastic potentiometers for low noise

  • External 150W toroidal power supply 100% discrete power supplies for audio path

  • Long lasting, stainless steel hardware


The Avalon AD2055 Pure Class A music equalizer is the most powerful, low noise parametric equalizer available today. Designed to optimize absolute signal integrity and musical performance, the AD2055 combines the best of active and passive filter topologies with sonic excellence unequaled by lesser designs. The AD2055 is the perfect solution for two buss music-program equalization, special instrument EQ and FX applications and ultra high performance mastering studio's.

Features include state-of-the-art, balanced 100% discrete, Pure Class A signal amplifiers, practical user features and rugged hardware designed to deliver true high performance audio for many years. 

Avalon equalizers feature the unique combination of both active and passive filter EQ designs. This special combination enables the AD2055 to deliver high speed transient detail at the operational extremes of real-world equalization demands. The passive high and low bands offer alternate musical tone range to the full function active parametric mid bands. Passive equalizers have long been a favorite with music lovers around the world.  Full bodied, powerful (up to +/-32dB, 64dB range !) and sweet frequency selections are the benefits of the passive high-low EQ bands. The full bandwidth twin mid bands provide variable frequency selection (X10 frequency multipliers for very wide range), variable Q (width) and amplitude control. 

Avalon's advanced true symmetry design offers high-voltage, large headroom, extended bandwidth and very low noise. The use of 100% discrete, Pure Class A signal amplifiers give the serious music professional unlimited sonic character and a natural harmonic detail that enhances the program material and becomes one with the music itself. The Avalon AD2055 breathes life!

Circuit Topology High-voltage 100% discrete, balanced and symmetrical Class A
Output Gain Range Unity Gain
Maximum Input Level +30dB balanced XLR pin 2 hot
Maximum Output Level +32dB balanced 600 ohms, DC coupled, high-current discrete Class A
Input / Output Type XLR type, pin 2 hot balanced
Noise 20kHz Unweighted -94dB (EQ in)
Distortion THD, IMD 0.5% (typical 0.05% at +6dB 1kHz)
Frequency Response -3dB 1Hz to 450kHz (input band limited)
Equalizer Type Passive high and low bands plus two fully parametric mid bands
Bypass Hard-wire relay bypass for equalizer in-out
Low Band F1 Passive, amplitude to -32dB to +32dB shelf or peak-dip curve
F1 Frequency Range Switched 10 position 18Hz, 25, 30, 50, 72, 100, 150, 215, 300, 450Hz
Mid Band F2 Active, amplitude to -16dB to +16dB peak-dip curve
F2 Frequency Range Variable 35Hz to 450Hz (x10) 350Hz to 4k5Hz, Q (width) 0.3 to 3.0
Mid Band F3 Active, amplitude to -16dB to +16dB peak-dip curve
F3 Frequency Range Variable 160Hz to 2k0Hz (x10) 1k6Hz to 20kHz, Q (width) 0.3 to 3.0
High Band F4 Passive, amplitude to -26dB to +26dB shelf or peak-dip curve
F4 Frequency Range Switched 10 position 1k5Hz, 2k5, 3k5, 5k, 7k2, 10k, 12k5, 15k, 20k, 25kHz
AC-DC Power External AC supply, 150w toroidal transformer, 4 pin cable 90v isolated,
(B2T Power Supply Included) 100-240v selectable 50/60Hz, 150w max
Dimensions 19 x 3.5 x 12 in (482 x 88 x 305mm)
Shipping weight 30lbs (13.6 kg)

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Tel: +1 949 492 2000
2023 Avalon Design USA LLC