DRAWMER DL441 – Quad Auto Compressor Limiter

The DL441 Quad Auto Compressor/Limiter captures four channels of Drawmer\'s innovative DL241 \'Auto Compressor\' in only 1U of rack space. The inclusion of new sophisticated \'automated\' circuitry allows the engineer to precisely control both the dynamic range and \'absolute\' peak level of the programme instantly, without sacrificing essential control parameters. This perfect balance of features makes the DL441 ideal for use in sound reinforcement and outside broadcast applications where an economy in rack space is essential. Each channel combines a fully professional \'Auto Attack/Release\' Compressor with a variable threshold \'Peak Level\' Limiter on the output providing a transparent \'endstop\'. High resolution bar-graph displays on each channel allow gain reduction and output level to be viewed simultaneously, of particular importance in darkened concert hall or control room situations.

Facilities available on the DL441 include:

Compressor : The compressor section can be switched to provide either HARD or SOFT knee compression In both the HARD and SOFT modes a Ratio control is available. In the SOFT mode the ratio increases gradually over a 10dB input level range until it reaches the ratio set on the front panel control, thus achieving a more natural sounding compression In HARD mode the compressor provides a more precise means of controlling gain, where the ratio as set on the front panel is applied immediately the signal exceeds threshold. This is particularly useful in many broadcast applications. HARD knee compression can also be used creatively as an effect, particularly in the treatment of drum and guitar sounds, or for giving rock vocals a \'compressed sound\'.

Auto Attack and Release : removes the need for manual adjustment by producing a response which constantly follows the dynamics of the signal. This enables the DL441 to preserve crisp transients without allowing excessive peaks to occur. A smooth yet lively recovery from compression minimizes side effects such as \'pumping\' and \'breathing\'. This feature is particularly valuable when the program being treated does not have predictable or consistent dynamics, such as complete mixes, vocals or \'slapped and pulled\' bass guitar.

Peak Level Limiter : \'Zero Response Time\', \'Zero Overshoot\' circuitry provides an absolute limit to the peak level of the output signal, adjustable from 0db to +16dB above system level. \'Zero Response Time\' transparent limiting means that the DL441 provides complete protection from even the fastest and shortest signal overloads, making the unit ideally suited for speaker system protection in sound reinforcement applications. The sophisticated circuitry will also prevent unpleasant distortion when used for digital mastering.

Metering : Comprehensive bar graph displays give \'at a glance\' indications of gain reduction, and input/output signal level Gain reduction from 1dB to 30dB is shown simultaneously with signal level from 10dB to +10dB. When the channel is in BYPASS the output bar graph displays the input signal level. Other single LEDs indicate function status of Hard/Soft compression, Bypass, Peak Limiting, Linking, and Power on.

Bypass : A fully balanced hard-wire bypass connects the input directly to the output allowing signal to pass through the unit with no power applied.

Stereo Linking : Channels 1-2 and/or 3-4 can be stereo linked, where the left channel of the stereo pair becomes the master.

Operating Level : The operating level of the DL441 can be instantly switched, independently on each channel, for either +4dBu or -10dBu operation using a rear panel push switch.

Input/Output : The DL441 is provided with balanced inputs and outputs on XLR connections.

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 

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) 

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)

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

• 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