AVALON VT-747 SP TWIN SIGNAL PATH OPTO-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.

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.
SIX BAND PROGRAM EQUALIZER
The VT-747SP equalizer utilizes 100% discrete, Class A high-voltage transistors
for optimum sonic performance. The six 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.

VT-747SP FEATURES 
Stereo Class A opto-compressor with spectral control
Stereo Class A six 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
 
VT-747SP SPECIFICATIONS
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 22lbs (10kg)
Dimensions-shipping carton  21 x 18 x 8 in (533 x 457 x 203mm)
Weight-packed 26lbs (11.8kg)

The Multicom Pro-XL MDX4600 gives you 4 channels of first-class dynamic
control in a single rack space. With a multitude of new features like the
advanced program-adaptive expander gate, extensive metering plus a variety
of configuration options, the Multicom Pro-XL puts a lot of dynamic processing
power in your rack.

Features
Switchable IKA (Interactive Knee Adaptation) program-adaptive compression
circuitry combines the advantages of hard-knee and soft-knee characteristics
IRC (Interactive Ratio Control) expander/gate circuitry for virtually inaudible noise
suppression
Switchable dynamic enhancer for brilliant, lively audio even with heavy compression
IGC (Interactive Gain Control) peak limiting circuitry combines clipper and program
limiter for reliable and inaudible protection against signal peaks
Switchable low contour filter prevents "pumping" due to low-frequency dominated
compression
Stereo couple function selectable for channels 1/2 and 3/4
Ultra low-noise 4580 operational amplifiers and state-of-the-art THAT¬ VCA's
Separate 8-segment LED meters for input/output levels and gain reduction
Selectable operating level (+4 dBu/-10 dBV)
High-quality detented ALPS¬ potentiometers and illuminated switches
Servo-balanced inputs and outputs with ? in. TRS and gold-plated XLR
connectors
Manufactured under ISO9000 certified management system

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.
OPTO-COMPRESSOR
The opto-compressor features a minimum signal path design with twin Class
A vacuum tube triodes for gain matching. The optical attenuator acts as a
simple passive level controller. Full dynamic control from soft compression to
hard- knee limiting can be achieved with threshold, ratio-compression, attack
and release controls plus gain reduction selection on the large VU meter. Special
spectral control including de-ess is available with the dual sweep mid EQ to side-
chain switch. The EQ section can be flipped pre or post the opto-compressor
via a front panel switch for alternate effects and tone shaping. Two VT-737SPs
can be linked via a rear panel link cable for stereo tracking. The compressor
bypass is a sealed silver relay for the most direct signal path.
SWEEP-EQUALIZER AND OUTPUT LEVEL
The VT-737SP equalizer utilizes 100% discrete, Class A-high-voltage transistors
for optimum sonic performance. The high and low frequency bands provide the
smooth characteristics of an all passive design, while the dual mid bands include
variable frequency and switched Q-width selection. The enhanced range of the mid
bands is extended into the high and low bands by the use of X10 frequency multipliers.
The bypass switch incorporates a sealed silver relay for the most direct signal path.
When the EQ to sidechain is engaged, the high-low EQ remains in the audio path for
"tone enhancement“. The output level control provides a variable control of the overall
signal path. The output amplifier utilizes another dual triode vacuum tube driving a
100% discrete, Class A, high-current, balanced and DC coupled low noise output
amplifier.

AVALON VT-737SP FEATURES
Vacuum tube triode signal path, transformer balanced microphone input, high-voltage
circuits for maximum headroom to +30dB, low noise -92dB, internal discrete power
supply with toroidal transformer, soft-start tube life extender, stereo link for compressors,
all discrete Class A equalizer with musical passive filter design, sealed silver relays for
signal routing, large control knobs with professional conductive plastic potentiometers,
VU meter for output level monitoring and compressor gain reduction.

VT-737SP SPECIFICATIONS
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 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)

Product Features:

Ultra-high resolution 24-bit/96 kHz mastering processor featuring 32/40-bit floating-point DSP technology
Audiophile 24-bit/96 kHz A/D- and D/A converters offering 113 dB dynamic range
4 concurrently selectable EQ modules (31-band graphic EQ, 10-band parametric EQ, Feedback Destroyer plus 3 Dynamic EQs per stereo channel)
Ultra-high resolution 61-band real-time FFT analyzer with additional auto EQ function for room and loudspeaker equalization
Unique VPQ (Virtual Paragraphic EQ) option allows parametric control of graphic EQs
State-of-the-art compressor/expander with peak limiter per stereo channel, additional stereo imager and stereo delay for delay line applications
Multi-functional level meters (peak/RMS, VU and SPL meter with dBA/dBC weighting via RTA/Mic input)
64 user memories for complete setups and/or individual module configurations
Separate mic/line input with phantom power for RTA and Auto-EQ applications
Balanced inputs and servo-balanced outputs with gold-plated XLR connectors, stereo aux output, AES/EBU and S/PDIF inputs and outputs (XLR and optical)
Professional Wordclock input and MIDI connections for full remote control, preset dumps and system updates
Open architecture allowing future software updates via MIDI
"Planet Earth" switching power supply for maximum flexibility (100 - 240 V~), noise-free audio, superior transient response plus low power consumption for energy saving
High-quality components and exceptionally rugged construction ensure long life
Conceived and designed by BEHRINGER Germany

dominated compression
Stereo couple function with independent output level settings
Switchable side chain input with side chain monitor function
Ultra low-noise 4580 operational amplifiers and state-of-the-art THAT¬ VCA's
Separate 12-segment LED meters for input/output levels and gain reduction
Dedicated "traffic light" threshold and de-esser level displays
High-quality detented ALPS¬ potentiometers and illuminated switches
Servo-balanced inputs and outputs with ? in. TRS and gold-plated XLR
connectors
Relay-controlled hard bypass switch with auto bypass function in case
of power failure
Manufactured under ISO9000 certified management system
 

Features
Four Independent Compressor Channels
Channels 1 and 2, 3 and 4 are stereo linkable
7 LED Gain Reduction metering
Balanced XLR Inputs and Outputs
Sidechain Insert points
Intuitive, user friendly layout
Flawless performance
 
The sheer amount of effects and signal processors necessary for today's standards
of audio production puts a great strain on the available space in equipment racks,
both in the studio and on the road.So, ARX would like to introduce the ARX Quadcomp.
An all-new upgrade of the classic award-winning ARX Quadcomp?, the very first four
channel 1 RU compressor.You?ll notice that we haven?t strayed very far from our
original design concept. The Quadcomp  is still four variable ratio Compressor/ Limiters
neatly housed in a compact all steel 1 RU package. However, all new low noise/low
distortion circuitry, better metering plus XLR inputs and outputs put the Quadcomp
in a class of its own.
More Control, Less Space
On the front panel, each channel has the 'industry standard' individual controls for Threshold,
Compression Ratio and Output, plus a new 7 LED Gain Reduction display for accurate visual
indication of the amount of gain reduction being applied to the program, and an IN/OUT
hardwire bypass switch.In addition to this, each channel has a blank numbered panel to write
on for easy confirmation of compressor assigns.
Precision Circuitry
Internally, each compressor uses Class A VCAs and true 2 pole averaging RMS/DC converters
for low distortion and accuracy, plus program dependent attack and release time, which
automatically determines optimum compressor response.
Balanced Inputs and Outputs
The rear panel has true differential Balanced XLR Inputs and Outputs for each compressor.
Each compressor has a TRS jack Sidechain access insert point, for frequency sensitive
compression, De-essing, etc. in conjunction with an external equalizer (such as the ARX EQ260).
Compressor pairs 1 and 2, 3 and 4 also have rear panel mounted Stereo Link switches for accurate
stereo tracking. When switched IN, the first channel becomes the master and controls all the functions
of the second except Output gain.
Universal AC Power
AC power range is switchable 100 to 120V, or 220 to 240V, and is connected to the unit via
a standard IEC connector, with built-in fuse and voltage switch.
Whatever the application ? Channel insert, Bus insert, Master Outputs, Monitor outputs,
Crossover outputs, the Quadcomp II?s unique High Density design, precision Low Noise circuitry
and clean uncluttered layout make it a truly useful audio tool for all applications.

T E C H N I C A L S P E C I F I C A T I O N S
Input Impedance
Balanced 20 Kohms, Unbalanced 10 Kohms
Input Headroom + 20dB
CMRR >50dB, 20 Hz?20 KHz
Output Impedance
Balanced 300 ohms Unbalanced 150 ohms
Output Level (Max) + 20 dB
Frequency Response 20Hz-20KHz ±0.5dB
Signal to Noise ratio
-93 dB Unweighted, -98 dB ?A? weighted
Distortion .015% THD @ 0dB,1KHz
Dynamic Range 108 dB
Attack and Release Times Program dependent
Metering
7 LED display: ?1, 2, 3, 6, 12, 18, ?24 dB
Sidechain Insert Impedance 10 Kohm
Power Requirements
100/120 V AC or 220/240 V AC
Weight 5 lbs/2.2 Kg
Dimensions
19“W x 1?“H x 6“D, 482 x 44 x 155mm
Input Connector type Balanced XLR
Output Connector type Balanced XLR
Sidechain Insert Connector TRS Jack

Front Panel Controls
Hardwire bypass IN/OUT switch
Threshold, Ratio and Output Gain controls
7 LED Gain Reduction display
Marker panel for labelling compressor assigns
Stereo link status LEDs
Rear Panel Connectors
Input and Output balanced XLR connectors
TipRingSleeve Sidechain insert connectors
Channels 1 and 2, 3 and 4 Stereo link switches
IEC AC mains connector with inbuilt fuse and
voltage change