Avalon 737SP features a combination of tube preamplifiers, opto-compressor, sweep equalizer, output level and VU metering in a 2U space. -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: Microphone: 26dB@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 to 20dB -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) BRAND NEW- STILL IN FACTORY BAG & BOX-NEVER USED !!!