Avalon Design VT-737sp mikrofonní předzesilovač

Avalon Design VT-737SP

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. A passive-variable high pass filter and hard-wire relay bypass completes the input signal conditioning. The phase reverse relay is available on all three inputs.

• 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: 482 x 305 x 89mm
• Weight: 11,8 kg