REVIEWS: From MIX |
AVALON DESIGN VT-737 VACUUM TUBE DIRECT SIGNAL PATH The latest addition to Avalon Design's high-quality line of preamps,
equalizers and compressors is the VT-737 Vacuum Tube Direct Signal Path,
a complete single-channel recording pathway for processing any audio
source, regardless of signal level or source impedance.When I think
of all the individual pieces of equipment I might have to patch together
to simply record avocal, the VT-737 seems like a godsend; it combines
all the functions of a mic tube preamp, tube optocompressor and a discrete
Class A transistor 4-band equalizer with sidechain routing ability,
all followed by a tube line level-balanced output stage. MIC PREAMP FRONT END A front panel switch selects three possible input sources: a rear XLR-
balanced line input to the equalizer and/or compressor sections; a front
%-inch unbalanced high-impedance (1-megohm) mic input for directly recording
instruments; and a rear transformer-balanced XLR input for studio mics.
With three input paths, you can immediately switch from recording a
direct guitar to recording a vocal to processing an already recorded
track with the EQ and compressor. There are also switches for 48 VDC
phantom power and (output) phase flip. Another switch selects a bass
cut filter operating between the preamp tubes; it's a -6dB/octave passive
design with a variable comer frequency of 30 to 140 Hz. OPTO COMPRESSOR The opto-compressor features two Class A triode tube sections. The optical
attenuator acts as a passive level controller. The Threshold control sets
threshold level from -30 to +20 dB with a center detent position of 0
dB. Preamp input gain and threshold settings are totally interactive;
shaping the nature of the compressed sound becomes something of a juggling
act between the controls. The VT-737 uses an all-discrete, Class A transistor circuit in the
4-band equalizer. The equalizer is divided into two separate equalizers:
a Treble/Bass EQ and a dual mid-band circuit. The Treble/Bass equalizer
is a passive, shelf-response design with +24 dI3 of gain. The Bass frequency
selection points are 15/30/60/150 Hz; Treble Frequency selection points
are 10/15/20/32 kHz. This part of the equalizer was very good, broad
and smooth. Even boosting at 32 kHz affected the high frequencies in
a subtle and positive way.But you can really carve in the equalizer's
dual mid-band section. The variable low-mid control selects the 35 to
450Hz range while the high-mid section affects from 220 to 2.8k Hz (t16
dB). Both sections have a "Hi-Q" switch that narrows the Gaussian curve
width from a Q of 0.2 to 0.8. A "x10" switch multiplies the indicated
frequency ten times. I'd like to see these sections fully parametric
with a little higher Q, but this may not be possible within this price/performance
envelope. The equalization was smooth and perfect for vocals but not
quite as cranky as I sometimes want when recording instruments such
as percussion or drums.
The internal toroidal power supply can be powered by any AC source
in the 100 to 240-volts range. An integrated "soft start," 40-second
power-up routine is said to enhance tube life, and Avalon recommends
following this with 30 minutes of warm-up time for optimum performance.
Maximum gain is 58 dB using the balanced mic input; maximum input level
is +10 dB at 25 Hz from the balanced mic input; maximum output level
is +30 dB into 600 ohms; EIN noise 20kHz unweighted is -92 dB; THD is
0.5%. |
Tel: +1 949 492
2000
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