Features Opto-compressor features a minimum signal path design with twin Class A vacuum tube triodes for gain matching AT4040 Switchable 80 Hz hi-pass filter and 10 dB pad The VT-737SP equalizer utilizes 100% discrete, Class A-high-voltage transistors for optimum sonic performance AT4040 Exceptionally low noise, wide dynamic range and high-SPL capability for greatest versatility High-voltage circuits for maximum headroom to +30dB Description Product Description The Avalon VT-737SP features a combination of TUBE preamplifiers, opto-compressor, sweep equalizer, output level and VU metering in a 2U space. PREAMPLIFIER. The VT-737SP has three input selections: 1. The VT-737SP features a higher-performance microphone input transformer with +48v phantom selection. 2. Instrument DI high source input with jack located on front panel. 3. Balanced line input, discrete high-level Class A. 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.   The AT4040 side-address condenser microphone features an advanced large diaphragm tensioned specifically to provide smooth, natural sonic characteristics. A marriage of technical precision and artistic inspiration, the AT4040 offers exceptionally low noise, wide dynamic range and high-SPL capability for greatest versatility. This ultra-consistent microphone may be used with confidence in a wide variety of studio and live miking applications, even under the stringent demands of digital recording systems. The AT4040's low-noise circuitry is symmetrical and transformerless, resulting in exceptional transient response and clean output signals for transparent reproduction of even the most troublesome of instruments and sound effects.