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)

Description

The alphaton Feedback-Controller FC-100 is a revolutionary product for every microphone
application including wireless types. It can provide effective feedback control to any sound
reinforcement situation. It can also eliminated string feedback in guitars and bass instruments
which are equipped with piezo or condenser pickups.
The FC-100 provides 6 to 10 dB of feedback protection by analysing the incoming signal,
detecting the presence of feedback and then notching out the feedback frequency.
The FC-100 relieves the sound engineer automatically. It works dynamically and eliminates a
feedback signal before it can grow into a peak. Internally a discriminator circuit detects the
presence of regenerative feedback and triggers the automatic equaliser to insert a notch where
the feedback peak is coming up. This normally prevents other peaks from developing but if they
do, the process is repeated at high speed, thus keeping feedback under control.

Technical Data
In- and Outputs transformer balanced
max. Inputlevel + 3 dB
Gain (RS=200 Ohm, RL=2kOhm) 0 dB
Frequency Response 20 Hz ... 20 kHz, +/- 1,5 dB
Feeback Cancellation  6 ... 10 dB
Power Requirement  30 ... 48 V Phantom
Current drain ca. 8 mA
External Power Supply 9 ... 20 V DC, 3,5 mm jack, tip +
Housing Aluminium Diecast
Weight  285 grams
Dimensions  112 x 60 x 32 mm

• Error proof operation to smooth uneven levels, add sustain to guitars, fatten drums or tighten up mixes
• New gate timing algorithms ensure the smoothest release characteristics
• Program-adaptive expander/gates
• Great sounding dynamics control for any type of program material
• Separate precision LED displays for gain reduction, compression threshold and gate threshold allow quick, accurate setup
• Stereo or dual-mono operation
• Balanced inputs and outputs on 1/4" TRS and XLR connectors
• Side Chain insert
• Classic dbx® "Auto" mode

The S com 4 is a compact and versatile single-rack space device that provides
four channels of high quality dynamics processing with an Expander/Gate and
Compressor/Limiter on each channel.
The four channels operate independently or in stereo pairs. Its multi-segment LED
metering displays input/output level as well as gain reduction. The Expander/Gate
section features a continuously variable Threshold control as well as a switch for
fast or slow release times.
The Compressor/Limiter section includes variable Threshold, Ratio and Output levels.
S com 4's Enhancer switch restores high frequencies that are sometimes diminished
by heavy compression. This wide-ranging combination of features makes the S com
4 an efficient and versatile audio tool for a wide variety of applications. Its clean and
quiet audio characteristics make it ideal where high sonic integrity is imperative. 
 
FEATURES:

4 Channel Compressor/Limiter, Expander/Gate with Enhancer
Linkable in two Stereo pairs
Expander/Gate with variable Trigger control and switchable Fast/Slow Release
5 Segment LED meters for Input/Output levels and Gain Reduction on each channel
Advanced circuit design utilizing Low Noise Operational
Amplifiers and High Quality VCA's
Servo Balanced Inputs and Outputs on XLR and 1/4" connectors
SKD (Smart Knee Detector) circuit automatically switches from soft to hard knee
based on the level of Input signal applied
Individual Threshold and Ratio controls on each channel
Three-year extended warranty 

Features
Enhance switch to restore spectral balance of compressed signal
Switchable Mode - Dual Channel or Stereo linked
Above or Below Threshold LEDs
Balanced XLR and Jack Inputs and Outputs
Intuitive, user friendly layout
Flawless performance

Innovation
The ARX COMPO? is a unique compressor/limiter designed for use in any
professional audio dynamics control application, packaged in a compact 1
RU chassis.The COMPO operates as two independent compressor/limiters,
with 'industry standard' variable Threshold, Ratio and Output gain controls.
A Stereo Link switch on the front panel lets both channels track as a stereo
pair in a Master/Slave configuration.
Enhance Switch
The COMPO features an 'Enhance' switch, which provides frequency restoration
to preserve the spectral balance of the audio signal, compensating for the sagging
Low and High frequency response of compressed program material.
The best way to think of it is as a 'smart' loudness control.
Wide Scale metering
There is comprehensive LED indication of all operating functions and status. Above
or Below Threshold LEDs on each channel give you instant visual confirmation of
compressor activity, as well as easy to read LED Gain Reduction meters.
Balanced Inputs and Outputs
On the rear panel, each channel has true differential Balanced inputs and outputs,
on both XLR and TRS jack connectors. Other features include an Active/Bypass
switch for each channel, and passive RFI filters on the inputs.
Universal AC Power
AC power range is a universal 100 to 120V or 220 to 240V AC, and is connected to
the unit via a removable power lead and standard 3 pin IEC connector, with built-in
fuse and voltage change switch.
ARX Quality
With its smooth compression, intuitive user friendly layout, high density precision
circuitry, and extensive user-variable operating parameters, the ARX COMPO is the
ideal installation 'set and forget' compressor, and is also equally at home in Studio,
Broadcast and Sound Reinforcement environments.

Every day, ARX Audio interface products solve audio problems for thousands of people
around the world.

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 + 22 dB
CMRR >60 dB, 20 Hz-20 KHz
Output Impedance Balanced 300 ohms, Unbalanced 150 ohms
Output Level (Max) + 22 dB
Frequency Response 20Hz to 20KHz ±0.4dB
Signal to Noise ratio -85 dB Unweighted, -99 dB 'A' weighted
Distortion .02% THD @ 0dB,1KHz
Dynamic Range 107 dB
Enhance Section
Low Enhance 50 Hz, High Enhance 10 KHz
Power Requirements 100/120 V AC, 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/OutputConnector type XLR, Balanced Jack

Front Panel Controls
Channel A Active/Bypassed IN/OUT switch
Threshold, Ratio and Output Gain controls
Numbered marker panel for labelling compressor assigns
5 segment LED Gain Reduction display
Above/Below Threshold status LEDs
Enhance switch and status LED
Stereo link switch and status LED
Channel B controls identical to Channel A
Rear Panel Connectors
Balanced XLR Input and Output connectors.
Balanced TRS jack Input and Output connectors.
AC input connector, with voltage switch and fuse.
 

The AD2055 combines 100% discrete, pure class A signal amplifiers with state-of-
the-art passive and active filter topologies. The AD2055's unique circuitry delivers
very high resolution transient detail at the operational extremes of real world equalization
demands. The AD2055 auto-bias DC servo loop control eliminates the need for all
interstage capacitor coupling. The AD2055 breathes life into all musical performances!
 
AD2055 FEATURES
Pure Class A, 100% discrete design
Smooth musical detail and sonic excellence
Minimum audio signal path
Dual mono operation
Transparent active and passive filter design
High headroom +30dB Very low noise -94dB
Fully balanced inputs and outputs
DC coupled, no transformers in audio path
Switched frequencies in high and low bands
Mid bands use X10 frequency for extended range
Wide bandwidth -3dB 1Hz to 450kHz
Low distortion less than 0.5% THD and IMD
All signal routing with sealed silver relays Conductive
plastic potentiometers for low noise
External 150W toroidal power supply 100% discrete
power supplies for audio path
Long lasting, stainless steel hardware
 
SONIC EXCELLENCE
The Avalon AD2055 Pure Class A music equalizer is the most powerful, low noise
parametric equalizer available today. Designed to optimize absolute signal integrity
and musical performance, the AD2055 combines the best of active and passive filter
topologies with sonic excellence unequaled by lesser designs. The AD2055 is the
perfect solution for two buss music-program equalization, special instrument EQ and
FX applications and ultra high performance mastering studio's.

Features include state-of-the-art, balanced 100% discrete, Pure Class A signal amplifiers,
practical user features and rugged hardware designed to deliver true high performance
audio for many years. 

PASSIVE-ACTIVE FILTER DESIGN
Avalon equalizers feature the unique combination of both active and passive filter EQ designs.
This special combination enables the AD2055 to deliver high speed transient detail at the
operational extremes of real-world equalization demands. The passive high and low bands offer
alternate musical tone range to the full function active parametric mid bands. Passive equalizers
have long been a favorite with music lovers around the world.  Full bodied, powerful (up to +/-32dB,
64dB range !) and sweet frequency selections are the benefits of the passive high-low EQ bands.
The full bandwidth twin mid bands provide variable frequency selection (X10 frequency multipliers
for very wide range), variable Q (width) and amplitude control.

MINIMUM SIGNAL PATH DESIGN
Avalon's advanced true symmetry design offers high-voltage, large headroom, extended bandwidth
and very low noise. The use of 100% discrete, Pure Class A signal amplifiers give the serious music
professional unlimited sonic character and a natural harmonic detail that enhances the program
material and becomes one with the music itself. The Avalon AD2055 breathes life!

AD2055 SPECIFICATIONS
Circuit Topology  High-voltage 100% discrete, balanced and symmetrical
Class A 
Output Gain Range  Unity Gain 
Maximum Input Level  +30dB balanced XLR pin 2 hot 
Maximum Output Level  +32dB balanced 600 ohms, DC coupled, high-current
discrete Class A 
Input / Output Type  XLR type, pin 2 hot balanced 
Noise 20kHz Unweighted  -94dB (EQ in) 
Distortion THD, IMD  0.5% (typical 0.05% at +6dB 1kHz) 
Frequency Response -3dB  1Hz to 450kHz (input band limited) 
Equalizer Type  Passive high and low bands plus two fully parametric mid
bands 
Bypass  Hard-wire relay bypass for equalizer in-out 
Low Band F1  Passive, amplitude to -32dB to +32dB shelf or peak-dip curve 
F1 Frequency Range  Switched 10 position 18Hz, 25, 30, 50, 72, 100, 150, 215,
300, 450Hz 
Mid Band F2  Active, amplitude to -16dB to +16dB peak-dip curve 
F2 Frequency Range  Variable 35Hz to 450Hz (x10) 350Hz to 4k5Hz, Q (width)
0.3 to 3.0 
Mid Band F3  Active, amplitude to -16dB to +16dB peak-dip curve 
F3 Frequency Range  Variable 160Hz to 2k0Hz (x10) 1k6Hz to 20kHz, Q (width)
0.3 to 3.0 
High Band F4  Passive, amplitude to -26dB to +26dB shelf or peak-dip curve 
F4 Frequency Range  Switched 10 position 1k5Hz, 2k5, 3k5, 5k, 7k2, 10k, 12k5,
15k, 20k, 25kHz 
AC-DC Power  External AC supply, 150w toroidal transformer, 4 pin cable 90v
isolated, 
(B2T Power Supply Included)  100-240v selectable 50/60Hz, 150w max 
Dimensions  19 x 3.5 x 12 in (482 x 88 x 305mm) 
Shipping weight  30lbs (13.6 kg)