Avalon VT747SP Class A Tube Stereo Compressor/Equalizer

The Avalon VT-747SP combines a creative STEREO tube-discrete Class A spectral-opto-compressor with a musical six band program equalizer, L-R output level and gain reduction metering and internal regulated power supplies in a 2U space. Ideal for high performance DAW input signal conditioning, stereo buss compression-EQ, stereo keyboards and analog mastering applications.

Features
Stereo Class A opto-compressor with spectral control

Stereo Class A 6- band discrete passive program EQ

TSP twin signal path, vacuum tube bypass

Low noise -92dB

Fully balanced Class A input and DC coupled outputs

Stereo dynamic 60dB high resolution output meters

High quality analog VU meter for gain reduction

High headroom+36dB input before overload

Spectral side-chain monitor for pre listen

EQ pre-post selection for opto-compressor

Sealed silver relays for all signal routing

Internal discrete regulated power supplies

Military spec vacuum tubes for long life and low noise

Spectral-Opto-Compression
The opto-compressor features a minimum signal path design utilizing sealed silver relays for all signal routing and by pass functions. The optical attenuator acts as a passive level controller with a Class A, variable gain make-up amplifier. Full dynamic control from soft compression to hard-knee limiting can be achieved with master threshold, ratio-compression, attack and release controls. Gain reduction indication is a large analog VU meter. Low frequency and high frequency contour parametric spectral controls can be routed into the side-chain path for enhanced frequency dependent compression with variable frequency and threshold levels. SC listen provides side-chain listen mode for monitoring.

6-Band Program Equalizer
The VT-747SP equalizer utilizes 100% discrete, Class A high-voltage transistors for optimum sonic performance. The 6-band stereo program EQ incorporates the smooth characteristics of an all passive design. The frequency turnover, Q and amplitude ranges have been carefully chosen for each band to provide the most natural harmonic balance and lowest phase change while offering simple and effective tone control. The EQ can be placed pre or post the opto-compressor for enhanced effects.

TSP - Twin Signal Path
The VT-747SP features TSP which gives you the choice of either tube tone or the classic, Class A discrete transistor sound by exchanging, three (3) high-voltage dual triode tubes with discrete amplifiers in the opto-compressor and primary output stages.

Input-Output and Metering
Fully balanced DC coupled, Class A discrete amplifiers are utilized for the input and output drive interface with+36dB input headroom. A high quality analog VU meter indicates accurate gain reduction. Twin 60dB range LED meters provide fast L-R output status of all levels.

Technical Info

Circuit topology Three (3) dual triode vacuum tubes (Sovtek 6922), high-voltage discrete Class A mode.

Input gain range Balanced, Class A, 20k ohms, -20dB to +16dB with high gain switch

Maximum input level +36dB balanced XLR pin 2 hot

Maximum output level +30dB balanced 600 ohms, DC coupled, discrete Class A

Output type XLR connector, output trim gain -45dB to +6dB

Noise 20kHz unweighted -92dB

Distortion THD, IMD 0.5%

Frequency response -3dB 1Hz to 200kHz

Gain reduction meter High quality, illuminated gain reduction meter 0dB to -20dB range

Output meter Twin 20 segment LED VU meters with -27dB to +30dB range

Compressor type Optical passive attenuator

Make-up gain Variable 0dB to +10dB stereo tracking

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

Side-chain spectral contour Variable threshold -15dB to +15dB, frequency 70Hz to 9kHz twin ranges

Equalizer type Discrete Class A, passive design optimized for full range program material

Frequency bands (6) Variable amplitude LF +/-24dB 15Hz shelf response

Variable amplitude MF1 +/-8dB 125Hz selected Q response

Variable amplitude MF2 +/-4dB 500Hz selected Q response

Variable amplitude MF3 +/-4dB 2kHz selected Q response

Variable amplitude MF4 +/-10dB 5kHz shelf response

Variable amplitude HF +/-20dB 32kHz shelf response

AC power Internal toroidal 100v to 240v, 50-60Hz selectable, 70 watts maximum

Dimensions 19 x 12 x 3.5 in. (482 x 305 x 89mm)

Weight 22 lbs. (10kg)

Dimensions-shipping carton 21 x 18 x 8 in. (533 x 457 x 203mm)

Weight-packed 26 lbs. (11.8kg)

Class A tube spectral opto-compressor with a 6-band program equalizer! Twin signal paths for choosing tube or solid state tone. Ideal for pre-DAW stereo signal conditioning, stereo bus compression/EQ, stereo keyboards, and analog mastering. XLR I/O.