Avalon Design VT-737SP Silver (B-Stock)

Mic Preamp

CAP2: 333250.0
£3,599.00 £3,999.00
£2,999.17 ex VAT
in stock

Beautifully engineered, mono 2U rack-mounted Class A valve channel strip with preamp, EQ and optical compressor


This B-Stock unit comes in original packaging, as new.

A full warranty of one year will be issued with this purchase.

Condition: EXCELLENT


At a glance

  • Hight quality discrete Class A Valve Mic Preamp
  • Mic / Line and Instrument DI input
  • Optical compressor incorporating twin Valves and stereo link option
  • Discrete Class A Equaliser, variable active and switched passive design
  • Hand made in the USA


The Avalon VT-737 SP is a single-channel valve channel strip with Class A Circuitry, Opto compressor and sweepable four-band EQ.

The Avalon VT-737 has been the channel strip of choice on countless classics for its ability to add warmth, sweetness and vibrancy to even the dullest microphones.

The preamp section includes high-level Class A circuitry with two cascaded dual vacuum tube triodes designed to provide minimal negative feedback and retains a purer sound. Three inputs can be selected from Mic level input, Line level input and DI instrument input. The preamp section includes a passive and variable high-pass filter, phase polarity and bypass.

This is followed by an opto-compressor with a ratio control ranging from 1:1 to 20:1, Threshold, attack and release controls. The Opto compressor uses an optical cell for passive attenuation and twin Class A vacuum tubes for gain matching, all in a minimal signal path to keep the signal as pure as possible. The compressor can be set to pre- or post-eq via a dedicated switch on the front panel. The EQ can also shape the side-chain path offering dynamic spectral shaping capabilities such as De-essing. The large VU meter can display input, output or gain reduction. A link Jack input can link two vt737-SP together for stereo tracks.

Finally, a four-band EQ includes Low- and high-shelf and two parametric bands. Low and high-shelves use passive designs offering a smooth sound with selectable frequencies. The two mid-bands include variable frequencies with a switched Q-width selection. Both mid-bands can also affect low and high bands thanks to the X10 frequency multipliers. The EQ is ideal for quick and tone enhancement. While in Sidechain mode, low and high shelves remain in the audio path to offer broad sound shaping.

The final output stage uses another dual triode valve to drive the discrete Class-A output amplifier.

  • Circuit topology: 4 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: Microphone26dB@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 to20dB
  • Noise 20kHz unweighted: -92dB
  • Noise microphone EIN: -116dB, 22Hz-22kHz unweighted
  • Distortion THD, IMD: 0.5%
  • Frequency response -2.5dB: 10Hz-120kHz input filter included
  • Frequency response -3dB: 1Hz-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-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-28kHz and 2kHz -28kHz, +/-6dB range, hi-lo Q Low mid - variable 30Hz-450Hz and 300Hz-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
  • Dimensions: 19 x 12 x 3.5 in (482 x 305 x 89mm)
  • Weight: 22lbs. (10kg)

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