Avalon Design VT-737SP

The unit was built for situations where an engineer needs a complete signal chain without patching several separate boxes together. The preamp section runs two cascaded dual triode vacuum tubes with minimal negative feedback, a transformer-balanced mic input with +48V phantom power, a front panel DI input, and a balanced Class A line input. A high-gain switch boosts overall preamp gain, while a passive variable high-pass filter and hard-wire relay bypass let you shape the input without coloring the tone unnecessarily.

Three Inputs, One Signal Path

A session rarely stays on a single source type. The VT-737SP switches between a microphone, a DI'd guitar and a line-level feed from another device without repatching between separate preamps. Phase reverse is available on all three inputs, which removes phasing headaches when doubling a vocal or capturing an acoustic instrument with two mics at once.

Opto-Compression and De-Essing Without an Extra Box

The opto-compressor uses twin Class A tube triodes for gain matching and gives full control over threshold, ratio, attack and release, with gain reduction read off the large VU meter. An EQ-to-sidechain switch routes the mid band of the equalizer into the compressor's sidechain, effectively delivering de-essing without patching in a separate processor. The EQ section can be flipped pre or post compressor, changing how the compression reacts to the source material.

The four-band equalizer is 100% discrete Class A. High and low bands are passive for a smooth character, while the two mid bands are sweepable in frequency and Q, with range extended by a x10 frequency multiplier. A tube-driven output stage feeds a fully discrete, balanced, DC-coupled Class A low noise output amplifier. Two VT-737SP units can be linked via a rear panel cable for matched stereo operation.

KEY FEATURES

• Single channel strip: preamp, opto-compressor and EQ in one 2U chassis
• Three inputs: transformer mic with +48V, instrument DI, balanced Class A line
• Four vacuum tubes configured as dual triodes
• Switchable high-pass filter and hard-wire relay bypass
• Phase reverse on all three inputs
• Opto-compressor with threshold, ratio, attack and release controls
• EQ-to-sidechain switch for de-essing
• EQ section switchable pre or post compressor
• Four-band discrete Class A EQ with sweepable mid bands
• Large VU meter switchable between output level and gain reduction
• Two units linkable for stereo operation

TECHNICAL SPECIFICATIONS

• Type: single channel tube channel strip
• Format: 19 inch, 2U rackmount
• Inputs: transformer mic, DI, balanced line
• Tube count: 4 (dual triodes)
• Compressor: opto, tube driven, Class A
• Equalizer: 4-band, discrete Class A, sweepable mid bands
• Output: balanced, discrete, Class A, DC coupled
• Metering: VU, switchable output/gain reduction
• Power: universal 100-240V, 50-60Hz
• Weight: 11.8 kg (26 lb)
• Country of manufacture: USA