Avalon VT-737sp
Tube Microphone / Instrument Preamplifier, Opto-compressor, and Sweep Equalizer
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The Avalon VT-737SP features a combination of tube preamplifier, opto-compressor, sweep equalizer, output level and VU metering in a 2U space. A great class A signal path from start to finish.
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Class A preamp
design with three input selections
The VT-737sp has
three input selections: First, it features a higher-performance microphone
input transformer with 48-volt phantom selection. Second, the VT-737sp offers
an instrument DI high-source input with a jack located on front panel. Finally,
the VT-737sp includes a balanced line input with discrete high-level Class A
circuitry. 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 hardwired relay bypass completes the VT-737sp's input
signal conditioning. A phase reverse relay is available on all three inputs.
Opto-compressor with minimum signal path
The VT-737sp's 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 VT-737sp's 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.
Sweepable EQ and hardwired bypass
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 Channel Strip Features :
- Class A preamp design with three input selections
- Opto-compressor with minimum signal path
- Sweepable EQ and hardwired bypass
- Vacuum tube and discrete design
- Ideal vocal chain for DAW digital recording and live touring rigs
- Wide range of tube tone and control
- Excellent value for performance
- Rugged Avalon construction
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
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
to 22kHz unweighted
- Distortion THD, IMD 0.5%
- 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
- Dimensions 19 x 12 x 3.5 in (482 x
305 x 89mm)
- Weight 22lbs (10kg)
- Dimensions-shipping carton 21 x 18
x 8 in (533 x 457 x 203mm)
- Weight-packed 26lbs (11.8kg)
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