It has +/-16dB amplitude control and a
high/low Q (bandwidth) swtich which musically
sharpens the filter’s response from a Q of 0.2
(wide) to 0.85 (medium). The High Mid band
filter section is of the same type and covers a
frequency band of 200Hz to 2.8kHz. With the
X10 switch engaged, the filter covers the 2kHz
to 28kHz range. A high/low Q switch changes
the bandwidth in the same way as the Low Mid
band.
The output stage of the Vt-737sp is another
twin-triode vacuum tube stage driving a
balanced low-noise Class A DC-coupled
output amplifier. This stage includes an output
level control to give the final level adjustment
before leaving the unit via an XLR connector.
Inside view of Vt-737sp
1.2 Features
• Natural balanced musical performance
•
100% discrete pure Class A operation
•
Three simultaneously available inputs
•
Vacuum tube opto-compressor
•
Four-Band active-passive equalizer
•
Two-band EQ side-chain filter
•
Variable high-pass filter on all inputs
•
Twenty-two silver relays for signal routing
•
True hard-wired Bypass
•
Low noise, better than -90dB
•
High operating headroom +30dB
•
Fully balanced operation
•
Advanced microphone transformer
•
High-Z one megohm instrument input
•
Balanced line input +36dB
•
Tube-discrete balanced output amplifier
•
4 military grade dual triode vacuum tubes
•
High voltage signal path
•
2U nineteen inch welded steel chassis
•
Swtichable AC power supply 100-240V
•
150W toroidal shielded power transformer
•
Discrete soft-start DC power regulators
Avalon Vt-737sp Operation Manual Page 7
Introduction