RDL TX-AT1 AUDIO ISOLATION TRANSFORMER 600 ohms, 1:1, terminals

These modules are intended to interface consumer audio equipment with professional balanced-line circuits, providing galvanic isolation in addition by the use of transformers, to avoid ground-loops and thus reducing hum.

TX-A2 - Balanced to unbalanced - Terminals, RCA (phono)

This converts a single, balanced, line input into two unbalanced outputs, with a reduction in level to suit the inputs of equipment such as consumer audio and video equipment, using a 'studio-quality' transformer for isolation. The front panel of the aluminium enclosure has a detachable terminal block for the input and two gold-plated RCA (phono) connectors for the outputs. Each output is coupled through an attenuation network that produces a nominal -10dBV level.

Input: +4dBu nominal, +22dBu max, detachable terminal block. Outputs: -10dBV, nominal. Response: 20Hz - 20kHz +/- 0.5dB. Distortion: 0.05%, 20Hz - 20kHz, +4dBu input; 0.01%, 1kHz. Dimensions: 61 x 76 x 40mm.

TX-A2D - Balanced to unbalanced - Terminals, RCA (phono) - dual

Similar to the TX-A2, this converts two balanced line inputs each into a single unbalanced output using two transformers, again with attenuation to suit consumer equipment. The front panel has two detachable terminal blocks for the inputs and two gold-plated RCA (phono) connectors for the outputs.

Technical specifications: As the TX-A2, except the following. Crosstalk: -80dB, 20hz - 20 kHz, referenced to -10dBV; -90 dB, 1kHz.

TX-AFC1F - Balanced to unbalanced - XLR3F, RCA (phono)

This converts a single, balanced, line input into a single unbalanced output, with a reduction in level to suit the inputs of equipment such as consumer audio and video equipment, using a 'studio-quality' transformer for isolation. The front panel has a 3-pole, female XLR connector for the input and a single gold-plated RCA (phono) connector for the output.

Input: +4dBu nominal, +22dBu max, 10k ohms. Output: -10dBV, nominal. Input balance: 85dB CMRR, 50-60Hz. Response: 20Hz - 20kHz +/- 0.1dB. Distortion: 0.06%, 50Hz - 20kHz, +4dBu input; 0.0015%, 1kHz. Dimensions: 61 x 76 x 40mm.

TX-AFC1M - Unbalanced to balanced - RCA (phono) to XLR3F

This converts a single unbalanced circuit, from, for example, the output of consumer audio and video equipment, to a balanced signal for use over longer distances and to avoid hum, since it uses a 'studio quality' transformer to provide galvanic isolation. The front panel has a single RCA (phono) connector for the input from the unbalanced equipment and a 3-pole male XLR for the output.

Input: -10dBV nominal, +22dBu max, 10k ohms. Insertion loss, input to output: 0.25dB, 20 ohms source, 10k ohms load. Response: 20Hz - 20kHz +/- 0.1dB. Distortion: 0.06%, 50Hz - 20kHz, -10dBV input; 0.0015%, 1kHz. Dimensions: 42 x 76 x 40mm.

Versatile building blocks in the popular Radio Design Labs TX packaging, which will mount directly to surfaces or using a range of mounting options. These modules provide auto changeover or manual switching.

TX-AVX Automatic Video Switch

A video changeover relay activated by the absence of a valid video signal on the main input signal. While a valid (video sync) signal is present the main input is connected to the output, which should be 75 ohm terminated. If the input signal becomes invalid or the power supply is interrupted, the output switches to the aux input. A switched ground signal output may be used to operate an alarm, and a fault LED is also provided. Input and outputs on BNC connectors.
Supply 12-33V DC or 12-24V AC, 100mA.

TX-MVX Manual Video Switch

A video changeover relay activated by pulling a trigger signal to ground, e.g. by an open collector slave output from other RDL modules, to provide automatic switching. Input and outputs on BNC connectors.
Supply 24-33V DC, 50mA.

TX-PCR1 Paging Controlled Relay

With switch selecting inputs of 25/70/100V and up to 75w, 8ohm input when on 25V mode, this controlled relay triggers when any program material/paging source is applied. An ‘open-collector’ slave output is included to control other modules or equipment along with a DPDT (double-throw, double-pole) switching relay.

Input sensitivity can be adjusted using a trimmer pot with the sensitivity trigger being 30dB below the switch-selected constant voltage. A red LED illuminates when any audio level exceeds the set trigger threshold. The delay is adjustable from 3 to 25 seconds via a trimmer positioned on the front panel. All inputs and outputs are via screw terminal block.
Supply 24V DC, 60mA.

TX-VCR Video Controlled Relay

A single pole changeover relay activated by the absence of a valid video signal on the loop through video signal. While a valid (video sync) signal is present the relay contact is closed, and when the signal is lost, it opens. Both normally closed and open contacts are provided so it can be configured as a video detection or video loss indicator. Sync and fault LED’s are also provided. Input and outputs on BNC connectors.
Supply 12-33V DC or 12-24V AC, 75mA.

TX-LC2 Audio Combiner (Unbalanced to Balanced)

For use when active, isolated mixing of two unbalanced line level audio sources to feed a balanced (or unbalanced) audio output, with common gain control, is required, eg. stereo to mono combining. Inputs are 10kHz bridging (–10dBv nom.) on 6.35mm mono jacks, and are isolated from each other. Gain adjustable +10dB to +24dB. Output 150R balanced (+4dBu nom.) on screw terminals. Supply: single 30mA.

TX-MX2R Audio Mixer

For use when active, isolated mixing of two unbalanced line level audio sources to feed one or two unbalanced audio outputs, with individual gain control, is required. Inputs are 10kHz bridging (-10dBv nom.) on 6.35mm mono jacks, and are isolated from each other. Gain adjustable 0dB to +6dB. Output 100R unbalanced (–10dBv nom.) on 6.35mm jack sockets. Supply: single 10mA.

TX-1W Music-on-hold Amplifier

For use where a PABX or key telephone system needs to be fed with music, speech, or a mixture of both. When a call is placed “on hold”, the audio quality perceived is affected by the caller’s own telephone earpiece, as well as the line quality and system design. Due to these variations, conventional audio amplifiers used as “music-on-hold” drivers often produce annoying artefacts to the caller. Attempts to reduce listener fatigue through HF roll-off alone tends to produce a muffled, tired sound. The TX-1W features a response specifically characterised to match the broadest variations in telephone audio distribution, producing a lively, crisp, interesting sound. Input on 6.35mm mono jack (–10dBv nom.), adjustable audio level –10dB to +25dB, unbalanced 1 watt output on 6.35mm mono jack, transformer balanced 600R output on screw terminals. Supply: single 150mA.

TX-PA40D Power Amplifier

This is a 'high-efficiency utility amplifier' which drives a pair of 4 or 8 ohm speakers. It is suited to applications where gain is controlled by other equipment, such as projectors with variable audio outputs used in classrooms, boardrooms and video conferencing. A stereo analogue compressor/limiter is included for 'audio fidelity noticeably superior to conventional class D amplifiers with digital limiting'. This can be adjusted so that the limiter alone is used for clipping suppression, or the full compressor/limiter can be used to substantially increase the average output power beyond that of a standard 40W amplifier.

When the limiter is clipping, normal audio level signals 'remain unaffected by the compressor thereby preserving audio dynamics'. If the input level is increased so the compressor is active, the audio is compressed according to three dynamic time constants 'providing aural transparency while maintaining clean, un-clipped, amplified audio for input overloads of up to 20 dB'. The TX-PA40D, with compression, is capable of 'producing average audio output levels and clarity normally expected from stereo amplifiers with a much higher output power rating'.

The front panel has two gold-plated RCA (phono), unbalanced input sockets, each with an associated screw-driver operated, gain-trim control. An input-mode slide switch, selects summed mono mode or stereo and another switch selects 8 or 4 ohms output loading. LEDs shows operation of the compressor-limiter and the presence of power. A detachable terminal block is provided for connection of the two loudspeaker feeds and power from the included inline power supply, which has an IEC AC power input. The module is equipped with both thermal and output short-circuit protection.

Inputs: -10dBV nominal, unbalanced, 10k ohms; -18dBV minimum to cross compressor threshold; +15dBV maximum. Response (note 1): 20Hz - 20kHz, +/- 1dB, 4 or 8 ohms. Distortion (note 1): 0.1% THD+N, 1kHz, 1W , 4 or 8 ohms; 1% ,50Hz - 20kHz, 8 ohms. Noise: 75dB below 20W RMS. Crosstalk: Better than 60dB, 1kHz, no compression. Compressor threshold: Nominally 2 dB below rated output, automatically adjusting attack and release times. Outputs: 20W RMS, 8 ohms, per channel; 15W RMS, 4ohms, per channel. Note 1: Measured at compressor threshold level equalling 12W RMS (8 Ohms) output power. Ambient temperature: 0- 40 degrees C; 20 degrees C recommended. Power source: 24V DC from included power supply, 100-240V C, 50-60Hz, 1.5A. Dimensions: 76 x 48 x 41mm.

TX-VLA1 Video Line Amplifier

A single channel video line amplifier with adjustable gain (unity to +5dB) and EQ (flat to +7 at 5MHz) to equalise cable runs up to 600 m. Input and outputs on BNC connectors.
Supply 12-33V DC or 12-24V AC, 30mA.

These modules provide an interface between balanced or unbalanced audio circuits and the three audio pairs in a Format-A chain. Passive types require no power, using a transformer to provide balanced connections and galvanic isolation. Active types use electronic balancing and also provide a connection to one Format-A chain to provide power for other sender and receiver modules either at an end-point of a chain or at a location between end-points.

The active modules themselves require a source of power at 24V DC, with a capability to provide sufficient current for all the modules connected to the chain. The power is connected to the module via a coaxial inlet or a detachable terminal block. Some modules may have both. The output power is protected by an automatically resetting fuse; and LED indicator is provided to show that the power is available. Power can also be provided by another module on the Format-A chain, through the RJ45 connector(s).

An LED on the front panel indicates when power is supplied to the module. All have connections for audio inputs, using detachable terminal blocks for balanced line connections operating at a nominal +4dBu, RCA (phono) sockets for connections using a nominal level of -10dBV, or both, depending on model.

All have at least one RJ45 connector to connect to the Format-A chain. Where there are also loop-in connectors to position the module at a point at a location between end-points, all 8 pins of the two connectors are wired in parallel, allowing A, B and C signals to pass through, as well as power from another module.

Feature matrix:

TX-TPS1A - Active, single pair, sender

This has two RJ45 connectors, for Format-A loop-in and output. A switch is used to select which of the Format-A signal pairs will be fed with the output of the module, A, B or C. Whichever pair is chosen should not have another sender connected elsewhere. Both RCA phono and terminal block connections are provided, one only should be used. Both a coaxial inlet and a detachable terminal block are provided for powering.

TX-TPS3A - Active, three pair, sender

This has three sets of both terminal block and RCA (phono) connections to feed three separate audio signals to the module. Either the terminal block or the RCA(phono) connector should be chosen for each signal. The signals are then buffered and sent out through a single RJ45 connector on pairs A, B and C of the Format-A chain. No other sending modules may be connected on the same cable as this module. Both a coaxial inlet and a detachable terminal block are provided for powering.

TX-TPS6A - Passive, single pair, sender

This has a single terminal block to connect a single signal to one pair of the Format-A chain. A transformer 'provides isolation' between the audio source and the RJ45 connectors connecting to the chain. There is a 'loop-in' connector and an output connector to connect to the Format-A chain. A switch is used to select to which signal pair, A, B or C, the module will feed. Whichever pair is chosen should not have another sender connected elsewhere. This is a passive module that does not require power to operate. If power is present on a cable connected to the loop-in RJ45 connector, that power is passed through to the modules connected to the output RJ45 connector.

These modules provide an interface between balanced or unbalanced audio circuits and the three audio pairs in a Format-A chain. Passive types require no power, using a transformer to provide balanced connections and galvanic isolation. Active types use electronic balancing and also provide a connection to one Format-A chain to provide power for other sender and receiver modules either at an end-point of a chain or at a location between end-points.

The active modules themselves require a source of power at 24V DC, with a capability to provide sufficient current for all the modules connected to the chain. The power is connected to the module via a coaxial inlet or a detachable terminal block. Some modules may have both. The output power is protected by an automatically resetting fuse; and LED indicator is provided to show that the power is available. Power can also be provided by another module on the Format-A chain, through the RJ45 connector(s).

An LED on the front panel indicates when power is supplied to the module. All have connections for audio outputs, using detachable terminal blocks for balanced line connections operating at a nominal +4dBu, RCA (phono) sockets for connections using a nominal level of -10dBV, or both, depending on model.

All have at least one RJ45 connector to connect to the Format-A chain. Where there are also loop-out connectors to position the module at a point at a location between end-points, all 8 pins of the two connectors are wired in parallel, allowing A, B and C signals to pass through, as well as power from another module.

Since the connections made to the Format-A signal pairs A, B and C are bridging (high impedance), up to ten receivers can be connected to each pair on the output of the module, so the signals can be distributed to different areas.

Feature matrix:

Optional accessories, active types: Power supplies, see RDL Power Supplies, or power inserters, see below, or any other Format-A module which supplies power on the chain in use.
Optional accessories, all receiver types: RDL Format-A sender module(s), see RDL Format-A modules.

TX-TPR1A - Active single-pair receiver

This has two RJ45 connectors, for Format-A input and loop-out. A switch is used to select which of the Format-A signal pairs will be used as the input to the module, A, B or C. Both RCA phono and terminal block output connections are provided. Both a coaxial inlet and a detachable terminal block are provided for powering.

TX-TRP2A – Active two-pair receiver

This has a single RJ45 connector for the input from the Format-A chain. Two sets of terminal block output connections are provided, corresponding to Format-A signal pairs B and C. Powered locally via coaxial inlet or remotely via RJ45.

TX-TPR3A - Active three-pair receiver

This has a single RJ45 connector for the input from the Format-A chain. Three sets of both terminal block and RCA (phono) buffered output connections are provided, corresponding to Format-A signal pairs A, B and C. Both a coaxial inlet and a detachable terminal block are provided for powering.

TX-TPR6A - Passive single-pair receiver

This has both an input and a 'loop-out' connector to connect to the Format-A chain. A switch is used to select to which signal pair, A, B or C, will feed the module. A single terminal block to and an RCA (phono) connector provide the output from the chosen pair. A transformer 'provides isolation' between the audio outputs and the RJ45 connectors connecting to the chain. This is a passive module that does not require power to operate. If power is present on a cable connected to the loop-in RJ45 connector, that power is passed through to the modules connected to the output RJ45 connector.

TX-TPSA1A Three-Pair Combiner to Single-Pair Sender

This module has one Format-A input on the front panel: the RJ45 connector accepts a three-pair Format-A twisted-pair cable with signals sent by from one or multiple Format-A senders. The module sums the signals received on the three pairs A, B and C. The summed output is fed to one of the pairs A, B or C on the output connector, as selected during installation using the switch on the front-panel.

The two remaining pairs are available for signals to pass through from other Format-A senders connected to the Loop-In RJ45 socket. The RJ45 Loop-In jack can accept two signals and power from other Format-A modules providing microphone or line inputs. Two single-pair senders can be connected to the Loop-In socket, or one sender that uses two pairs.

The TX-TPSA1A may be powered from any of the RJ45 connectors, which provides power to the two remaining RJ45 jacks. The module may also be powered from an external 24V DC power supply connected to the DC input socket, which provides power to all three RJ45 jacks. The power output is protected by an automatically resetting fuse. An LED on the front panel indicates the presence of valid power.

These modules provide a connection to one Format-A chain to provide power for sender and receiver modules from a convenient location, either at an end-point of a chain or at a location between end-points. The modules themselves require a source of power at 24V DC, with a capability to provide sufficient current for all the modules connected to the inserters. The power is connected to the module via a coaxial inlet or a detachable terminal block. Some modules may have both. The output power is protected by an automatically resetting fuse; and LED indicator is provided to show that the power is available. An LED on the front panel indicates when power is supplied to the module.

TX-TP1PW

This has two RJ45 connectors to provide power for one Format-A chain. The two connectors are connected in parallel, allowing signals on the A, B and C signal pairs of the two connectors to pass through the modules. The power supply is connected by either the coaxial power inlet or the detachable terminal block

TX-TP4PW

This has four RJ45 connectors to provide power for one Format-A chain. The four connectors are connected in parallel, allowing signals on the A, B and C signal pairs of the four connectors to pass through the modules. The module is powered via a coaxial inlet.

Example configurations:

One RJ45 connector receives signals from Format-A twisted pair senders. The remaining three RJ45 jacks each connect to a separate twisted pair receiver. Three jacks are provided so that three runs of cable to twisted pair receivers are possible. This is 'particularly useful for powering three high current receivers that cannot be daisy chained, such as D-PSP1A Powered Speakers'. In this configuration the TX-TP4PW might be thought of as a 'splitter'.

The reverse of the above, where three separate cables from separate Format-A senders converge at the TX-TP4PW. The fourth RJ45 becomes an output with signals on all pairs A, B and C. The TX-TP4PW in this configuration might be described as a 'combiner'. Apparently 'this is useful in installations where daisy chaining senders is not practical'.

RDL tell us that using a TX-TP4PW to 'send signals in both directions over a single Format-A cable' is a 'non- typical use. Advanced users only.'