D&R TELCOM Telephone Hybrid

If you need a simple portable telephone Hybrid, the TELCOM is the answer. It is small, can be mounted in a 19" rack (with an extra blind panel) and the telephone line powers the unit. So no dead batteries anymore. It can be connected to any mixing console by way of its Cinch or jack connectors on the back and to the telephone appliance and wall connector by its standard RJ 11 connectors. It provides you with balanced automatic line compensation to achieve optimum audio quality.

Telephone hybrids provide the interface between professional audio equipment and the public telephone network.

They provide protection for your equipment and the public telephone lines, allowing for varying line signals and line conditions. Automatically cancelling out the unwanted signal they also facilitate two-way communication down a single telephone line.

Each hybrid has a telephone line connection, a handset connection and separate connectors for audio input and output from a broadcast mixer, or other professional audio source.

A large proportion of D&R hybrids are used in radio and television broadcasting applications allowing external callers to be connected to the studio mixing console.

Most of the other units are supplied to communication operations allowing extremely effective conversion between 4-wire audio circuits and standard telephone lines.
The Telcom Hybrid does not need external power and can be used anywhere, powered from the telephone line, it also has an internal compressor that compensates for line level differences.

The DPR-504 is a 4-channel noise gate.

Each channel features:
A parametric key filter with key filter listening.
Simultaneous key level and threshold metering with average and
peak metering.
A gate status LED.
A RELEASE/HOLD control (hold tracks proportionally with release
times).
Attack switchable auto/fast (auto tracks signal dynamics for optimum
setting).
Link (links two channels together).
Key source allows external triggers.

The Range switch selects between 7OdB and 2OdB gating depth to
provide alternative release profiles.
The unit features electronically balanced inputs and outputs. 

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

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