Avalon

The Avalon VT-737SP is a channel strip featuring a combination of tube preamplifiers, opto compressor, sweep equalizer, output level and VU metering in a 2U space.PREAMPLIFIERThe VT-737SP has three input selections:The VT-737SP features a higher-performance microphone input transformer with +48V phantom selectionInstrument DI high source input with jack located on front panelBalanced line input, discrete high-level Class AThe 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.OPTO COMPRESSORThe 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.SWEEP-EQUALIZER AND OUTPUT LEVELThe 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 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.FEATURES:Vacuum tube triode signal pathTransformer balanced microphone inputHigh-voltage circuits for maximum headroom to +30 dBLow noise -92 dBInternal discrete power supply with toroidal transformerSoft-start tube life extenderStereo link for compressorsAll discrete Class A equalizer with musical passive filter designSealed silver relays for signal routingLarge control knobs with professional conductive plastic potentiometersVU meter for output level monitoring and compressor gain reduction

The Avalon VT737 SP Tube Voice Channel, delivers impeccable clarity with tube warmth and presence for your mic, instrument or line mono channel.The Avalon VT737 SP Mono Mic Pre/Compressor/EQ is a combination tube preamp, opto-compressor and sweep equalizer, with output level and VU metering in 2 rackspaces. Balanced mic, front-panel instrument DI, and balanced line inputs. Class A preamp uses 2 cascaded, dual vacuum-tube triodes configured with minimum negative feedback. The Avalon Vt 737sp has a high-gain switch, high-pass filter, and hardwire relay bypass..The main features of the Avalon VT737 SP include: Tube preampOpto-compressorSweep equalizerOutput level controlVU meteringBalanced mic input, front-panel instrument DI, and balanced line inputsHigh-gain switchHigh-pass filterHardwire relay bypass The main specifications of the Avalon VT737 SP include:Circuit topology: 4 dual triode vacuum tubes (Sovtek 6922), high-voltage discrete Class AGain Range Microphone: Transformer balanced 850/2500 ohm, 0dB to +58dB Instrument: Unbalanced 1 meg ohm, 0dB to +30dBLine: Balanced Class A 20k ohms, -27dB to 28dBMaximum input level and connector types: Microphone26dB@25Hz, +30dB@1kHz balanced XLR Instrument+30dB unbalanced front panel jack socketLine +36dB balanced XLRMaximum output level: +30dB balanced 600 ohms, DC coupled, discrete Class AOutput type and gain: XLR connector, output trim gain -45dB to20dBNoise 20kHz unweighted: -92dBNoise microphone EIN: -116dB, 22Hz-22kHz unweightedDistortion THD, IMD: 0.5%Frequency response -2.5dB: 10Hz-120kHz input filter includedFrequency response -3dB: 1Hz-200kHz line in-outVU meter and gain reduction: High quality illuminated OVU =+4dB and gain reduction to -20dBHigh cut filter: Variable 6dB per octave 30Hz-140HzCompressor type: Optical passive attenuator incorporating twin vacuum tubes and stereo linkThreshold - Ratio: Threshold variable -30dB to +20dB, ratio-compression variable 1:1 to 20:1Attack - Release: Attack variable 2mS to 200mS, release variable 100mS to 5 secondsEqualizer type: Discrete Class A, variable active and switched passive designFrequency 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, shelfAC power: Internal toroidal 100v to 240v, 50-60Hz selectable, 75 watts maximumDimensions: 19 x 12 x 3.5 in (482 x 305 x 89mm)Weight: 22lbs. (10kg)