Avalon 737

All About Avalon 737 | Features And Specs

The Avalon 737 gives everything in your studio a special touch.

It produces epic results with radio-ready gloss and detail for artists like Eric Clapton and The Rolling Stones, Jay-Z and Dr. Dre, Babyface and Beyonce, and Dr. Dre and Jay-Z.

You’ll be astounded by how warm and lovely it sounds when you run even the dullest, most sterile mic through the VT-737sp. Your recordings will be energised.

The Avalon VT-737SP combines

  • TUBE preamplifiers,
  • an Opto-compressor,
  • a sweep equaliser,
  • output level, and
  • VU metres.

Two cascaded, twin vacuum-tube triodes are used in a class A preamp with the least amount of negative feedback.

Moreover, the high-gain switch, high-pass filter, and hardwire relay bypass are top-notch features of the Avalon Vt 737sp.

The Avalon VT-737sp vacuum tube channel strip has become as the gold standard for emphasising a lead vocal after it was introduced in the 1990s.

The limited-edition black tube voice channel from Avalon VT737 SP. delivers unmatched clarity, warmth, and presence for your mic, instrument, or line mono channel thanks to the tubes.

AVALON 737 Features


The VT-737SP has three input selections:

1. The VT-737SP features a higher-performance microphone input transformer with a +48v phantom selection.

2. Instrument DI high source input with jack located on the front panel.

3. Balanced line input, discrete high-level Class A. The Class A preamplifier utilizes two cascaded, dual vacuum tube triodes configured with minimum negative feedback.

A high-gain switch boosts the overall gain of the preamplifier. The four high-quality tubes are configured as singled ended anode coupled followers. A passive-variable high pass filter and hard-wire relay bypass completes the input signal conditioning. The phase reverse relay is available on all three inputs.


The opto-compressor features a minimum signal path design with twin Class A vacuum tube triodes for gain matching.

The optical attenuator acts as a simple passive level controller.

Full dynamic control from soft compression to hard- knee limiting can be achieved with threshold, ratio-compression, attack and release controls plus gain reduction selection on the large VU meter.

Special spectral control including de-ess is available with the dual sweep mid EQ to side-chain switch. The EQ section can be flipped pre or post the opto-compressor via a front panel switch for alternate effects and tone shaping.

Two VT-737SPs can be linked via a rear panel link cable for stereo tracking. The compressor bypass is a sealed silver relay for the most direct signal path.


The VT-737sp equalizer utilizes 100% discrete, Class A-high-voltage transistors for optimum sonic performance.

The high- and low-frequency bands provide the smooth characteristics of an all passive design, while the dual mid bands include variable frequency and switched Q-width selection. The enhanced range of the VT-737sp’s mid bands is extended into the high and low bands by the use of X10 frequency multipliers.

The bypass switch incorporates a sealed silver relay for the most direct signal path. When the EQ to sidechain is engaged, the high-low EQ remains in the audio path for “tone enhancement.” The output level control provides a variable control of the overall signal path.

The output amplifier utilizes another dual triode vacuum tube driving a 100% discrete, Class A, high-current, balanced and DC coupled low noise output amplifier.

AVALON VT-737SP Key Features

  • Vacuum tube triode signal path,
  • transformer balanced microphone input,
  • high-voltage circuits for maximum headroom to +30dB,
  • low noise -92dB,
  • internal discrete power supply with toroidal transformer,
  • soft-start tube life extender,
  • stereo link for compressors,
  • all discrete Class A equalizer with musical passive filter design,
  • sealed silver relays for signal routing,
  • large control knobs with professional conductive plastic potentiometers,
  • Vacuum tube and innovative design
  • Perfect for DAW and digital recording
  • Wide range of tube tone and control
  • Excellent value for performance
  • VU meter for output level monitoring and
  • compressor gain reduction.

AVALON VT-737SP Specifications

Circuit topology

Four dual triode vacuum tubes (Sovtek 6922), high-voltage discrete Class A

Gain Range

Microphone: Transformer balanced 850/2500 ohm, 0dB to +58dB Instrument: Unbalanced 1 meg ohm, 0dB to+30dB Line: Balanced Class A 20k ohms, -27dB to 28dB

Maximum input level and connector types

Microphone: 26dB@25Hz, +30dB@1kHz balanced XLR Instrument+30dB unbalanced front panel jack socket

Line +36dB balanced XLR

Maximum output level

+30dB balanced 600 ohms, DC coupled, discrete Class A

Output type and gain

XLR connector, output trim gain -45dB to 20dB

Noise 20kHz unweighted


Noise microphone EIN

-116dB, 22Hz to 22kHz unweighted

Distortion THD, IMD


Frequency response -/2.5dB

10Hz to 120kHz input filter included

Frequency response -3dB

1Hz to 200kHz line in-out

VU meter and gain reduction

High quality illuminated OVU =+4dB and gain reduction to -20dB

High cut filter

Variable 6dB per octave 30Hz to 140Hz

Compressor type

Optical passive attenuator incorporating twin vacuum tubes and stereo link

Threshold – Ratio

Threshold variable -30dB to +20dB, ratio-compression variable 1:1 to 20:1

Attack – Release

Attack variable 2mS to 200mS, release variable 100mS to 5 seconds

Equalizer type

Discrete Class A, variable active and switched passive design

Frequency bands (4)

Treble – switched 10kHz, 15kHz, 20kHz, 32kHz, +/- 20dB range, shelf High mid – variable 200Hz to 2k8Hz and 2kHz to 28kHz, +/- 16dB range, hi-lo Q Low mid – variable 30Hz to 450Hz and 300Hz to 4k5Hz, +/- 16dB range, hi-lo Q Bass – switched 15Hz, 30Hz, 60Hz, 150Hz, +/- 24dB range, shelf

AC power

Internal toroidal 100v to 240v, 50-60Hz selectable, 75 watts maximum


19 x 12 x 3.5 in (482 x 305 x 89mm)


22lbs (10kg)

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