AT40T - Controller RCF - Free user manual and instructions

Product Type	Constant Voltage Line Volume Control with 40 W Transformer
Brand	RCF
Model	AT40T
Input Voltage	100 V
Output Voltage Levels	100 V, 70 V, 50 V, 35 V, 25 V, 0 V (off)
Maximum Power	40 W
Attenuation Steps	0 dB, -3 dB, -6 dB, -9 dB, -12 dB, OFF
Selector Positions	6 (5 volume + off)
Override Relay	24 V DC, bypasses selector or switches to second audio line
Wiring Options	2-wire, 4-wire (with override), 6-wire (second audio with priority), 3-wire (commutation)
Selector Weight	ca. 40 g
Transformer Weight	200 g
Mounting Hole Diameter	12 mm
Knob Colors Included	White, Silver, Anthracite
Installation	Fits standard electrical wall boxes (surface/flush) using a blank key
Operating Environment	Indoor, dry location only
Safety Certifications	Complies with local electrical regulations
Cleaning	Do not use solvents; wipe with dry cloth

Frequently Asked Questions - AT40T RCF

What is the maximum power handling of the RCF AT40T?

The AT40T can handle a maximum power of 40 W for the connected loudspeaker group.

What input voltage does the AT40T support?

It is designed for 100 V line systems. The input voltage is 100 V.

How many attenuation steps does the selector have?

The 6-position selector offers 5 volume steps (0, -3, -6, -9, -12 dB) and an OFF position.

Can I use the AT40T with a 24 V override for emergency paging?

Yes, it includes a 24 V DC override relay that bypasses the selector or switches to a second audio line for priority announcements.

What wiring configurations are possible?

You can use 2-wire (basic), 4-wire (with override), 6-wire (second audio line with priority), or 3-wire (commutation) connections.

How do I install the AT40T in a wall?

Use a blank key for standard electrical boxes. Drill a 12 mm hole in the center, mount the selector, connect wires, and fix the frame. Screw the nut and add a knob.

What are the output voltage levels available?

The transformer provides taps for 100 V, 70 V, 50 V, 35 V, 25 V, and 0 V (off).

Is the AT40T safe to use outdoors?

No, it is intended for indoor use only. Protect from rain and humidity to avoid electric shock.

How should I clean the volume control?

Use a dry cloth. Do not use solvents, alcohol, benzene, or other volatile substances.

What should I do if the device emits smoke or strange odor?

Immediately switch off the amplifier and remove the volume control from the line. Contact qualified service personnel.

USER MANUAL AT40T RCF

CONSTANT VOLTAGE LINE VOLUME CONTROL WITH 40 W TRANSFORMER

ATTENUATORE PER LINEA A TENSIONE COSTANTE CON TRASFORMATORE (40 W)

User manual Manuale d'uso

INDICE ITALIANO

Connections ____ page 13

Installation ____ page 18

Specifications ____ page 19

IMPORTANTE

3D diagram showing a wire-coated grid surface being processed by a tool, next to a metallic bracket with a circular hole (no text or symbols)

Simple diagram of a rectangular box with a central dot and three vertical divisions (no text or symbols)

Three technical line drawings of mechanical components or assemblies, showing cylindrical and rectangular parts with no visible text or symbols.

Pure electrical circuit lines without any symbols

Simple diagram of a rectangular box with a circular symbol on the left side (no text or labels)

Simple line drawing of a rectangular device with a handle and two circular buttons (no text or symbols)

Simple line drawing of a rectangular box with a circular button on the left side (no text or symbols)

Simple diagram of a rectangular box with a circular symbol on the top and three vertical panels inside (no text or labels)

Before connecting and using this product, please read this instruction manual carefully and keep it on hand for future reference. The manual is to be considered an integral part of this product and must accompany it when it changes ownership as a reference for correct installation and use as well as for the safety precautions. RCF S.p.A. will not assume any responsibility for the incorrect installation and / or use of this product.

WARNING: To prevent the risk of fire or electric shock, never expose this volume control to rain or humidity.

SAFETY PRECAUTIONS

1. All the precautions, in particular the safety ones, must be read with special attention, as they provide important information.
2. Loudspeaker lines (from amplifier outputs) can have a sufficiently high voltage (i.e. 100 V) to involve a risk of electrocution: never install or connect this volume control when the line is alive.
3. Make sure all connections have been made correctly, verifying that the line voltage matches the volume control specifications.
4. Protect loudspeaker lines from damage; make sure they are positioned in a way that they cannot be stepped on or crushed by objects.
5. Make sure that no objects or liquids can get into this volume control, as this may cause a short circuit.
6. Never attempt to carry out any operations, modifications or repairs. Contact your authorized service centre or qualified personnel should any of the following occur:
7. The volume control does not function (or works in an anomalous way).
8. Objects or liquids have got into the volume control.
   • The volume control has been damaged (due to heavy impacts or fire).

IMPORTANT NOTES

1. Should any part of the volume control emit any strange odours or smoke, remove it from the line after having immediately switched the amplifier off.
2. Do not connect this product to any equipment or accessories not foreseen.

Check the suitability of the support surface (wall, structure, etc., which the product is anchored to) and the components used for attachment (not supplied by RCF) that must guarantee the security of the system / installation over time, also considering, for example, the mechanical vibrations normally generated by transducers.

1. RCF S.p.A. strongly recommends this product is only installed by professional qualified installers (or specialised firms), who can ensure a correct installation and certify it according to the regulations in force.

The entire audio system must comply with the current standards and regulations regarding electrical systems.

1. There are numerous mechanical and electrical factors to be considered when installing a professional audio system (in addition to those which are strictly acoustic, such as sound pressure, angles of coverage, frequency response, etc.).
2. Hearing loss

Exposure to high sound levels can cause permanent hearing loss. The acoustic pressure level that leads to hearing loss is different from person to person and depends on the duration of exposure. To prevent potentially dangerous exposure to high levels of acoustic pressure, anyone who is exposed to these levels should use adequate protection devices. When a transducer capable of producing high sound levels is being used, it is therefore necessary to wear ear plugs or protective earphones.

1. Pay attention to all volume control terminal labels when connecting.
   To ensure a correct musical reproduction, loudspeaker phase is to be respected too.
2. To prevent inductive effects from causing hum, noise and a bad system working, loudspeaker lines should not be laid together with other electric cables (mains), microphone or line level signal cables connected to amplifier inputs.
3. Cables connected to this volume control shall have wires with a suitable section (twisted, if possible, to reduce inductive effects due to surrounding electro-magnetic fields) and a sufficient electrical insulation.

Refer to local regulations since there may be additional requirements about cable characteristics.

OPERATING PRECAUTIONS

• Install this volume control far from any heat source.
- Do not overload.
- Do not use solvents, alcohol, benzene or other volatile substances for cleaning the external parts of this product.

RCF S.p.A. would like to thank you for purchasing this product, which has been designed to guarantee reliability and high performance.

DESCRIPTION

AT 40T volume control is made of a control circuit having a selector and a separated transformer.

It can be used in 100 V line systems to adjust the volume level of a loudspeaker group having a total power not exceeding 40 W.

All connected loudspeakers shall have 100 V line matching transformers.

It includes a 24 V dc override relay to either bypass the 6 position (5 + off) selector or insert a second 100 V line (not affected by the volume control) for paging.

It can operate with 3 wire lines as well (in order to make emergency announcements without using the internal 24 V dc relay).

AT 40T can be installed on whichever supporting frame for home / office electrical systems by drilling a hole in a blank key and fixing the control circuit.

3 knobs are included in 3 different colours: white, silver, anthracite.

If there is enough room, the transformer can be put inside the wall / flush-mounted box (where the control circuit is).

graph LR
    A["AMPLIFIER"] -->|100 V| B["AT 40T"]
    B -->|max. 40 W| C["LOUDSPEAKERS"]
    B -->|max. 40 W| D["LOUDSPEAKERS"]

CONNECTIONS

WARNING: connections should be only made by qualified and experienced personnel having the technical know-how or sufficient specific instructions (to ensure that connections are made correctly) in order to prevent any electrical danger.

To prevent any risk of electric shock, do not connect volume controls / loudspeakers when the amplifier is switched on. Before turning the system on, check all connections and make sure there are no accidental short circuits. The entire sound system shall be designed and installed in compliance with the current local laws and regulations regarding electrical systems.

Example no. 1: basic 2 wire connection

- an audio input (100 V)

The 100 V input (IN) is directly connected to the Ji+ , Ji- (0, common) terminals and the transformer (100V, COM), of which outputs (having intermediate voltages) are connected to the J1 1/2, J1 1/4, J2 1/8, J2 1/16 terminals.

The output level (OUT: Jo+ and Jo- terminals) is selected by means of the 6 position selector (5 + off).

JPA and JPB jumpers are not influential (they can be left in the position 1-2).

Example no.2: connection with override relay (4 wire line)

• an audio input (100 V)
• a 24 V dc command

The 100 V input (IN) is directly connected to the Ji+ , Ji- (0, common) terminals and the transformer (100V, COM), of which outputs (having intermediate voltages) are connected to the J1 1/2, J1 1/4, J2 1/8, J2 1/16 terminals.

The output level (OUT: Jo+ and Jo- terminals) is selected by means of the 6 position selector (5 + off).

If necessary, the output level can be forced to its maximum (the selector is bypassed) through a 24 V dc command.

Both jumpers (JPA and JPB) are to be set to the position 1-2.

Example no.3: connection with the second audio line and the override relay (6 wire line)

• an audio input (100 V)
• a second audio input with priority (100 V)
• a 24 V dc command

The 100 V input (IN A) is directly connected to the Ji+, Ji- (0, common) terminals and the transformer (100V, COM), of which outputs (having intermediate voltages) are connected to the J1 1/2, J1 1/4, J2 1/8, J2 1/16 terminals.

The output level (OUT: Jo+ e Jo- terminals) is selected by means of the 6 position selector (5 + off).

If necessary, the second audio input for paging can be routed to the output (the selector is bypassed) through a 24 V dc command.

Both jumpers (JPA and JPB) are to be set to the position 2-3.

Example no.4: 3 wire connection

• an audio input
  (100 V) with 3rd wire
  (0 - 100 V exchange)

The 100 V input signal has 3 wires:

1. 100 V;
2. 0;
3. 0 (normal) / 100 V (override) commutation.

The first (100 V) and the third wire (0 / 100 V commutation) are directly connected (respectively) to the Ji+, Ji- terminals and the transformer (100 V, COM), of which outputs (having intermediate voltages) are connected to the J1 1/2, J1 1/4, J2 1/8, J2 1/16 terminals.

The second wire (0) is directly sent to the output (through the J4 terminal). The output level (OUT: Jo+ and J4 terminals) is selected by means of the 6 position selector (5 + off). If necessary, the output level can be forced to its maximum by commuting the 3rd wire voltage from 0 to 100 V (by using an additional external relay).

JPA and JPB jumpers are not influential (they can be left in the position 1-2).

INSTALLATION

Use a blank key for common electric wall surface / flush-mounted boxes.

Remove all ribs (if present) by using tongs.

3D illustration of a microelectronic component with grid pattern and two metallic parts (no text or symbols)

Drill the blank key in the centre. Hole diameter: 12 mm.

Simple diagram with a black dot inside a rectangular frame (no text or symbols)

Mount all blank keys into the frame. The first slot (on the left) is for the drilled blank key.

Three technical line drawings of mechanical components, showing cylindrical and rectangular parts with no text or symbols.

Screw the spacer into the selector.

After connecting all wires, put the selector printed circuit and the transformer into the box.

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Insert the selector shaft into the hole of the blank key rear side and fix the frame.

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Screw the nut to fix the selector to the blank key.

Simple line drawing of a rectangular panel with a circular button and two vertical slots (no text or symbols)

Simple line drawing of a rectangular device with a circular button on the left side (no text or symbols)

Add one of the 3 available knobs.

Simple diagram of a rectangular box with a circular symbol on the top and three vertical panels inside (no text or labels)

SPECIFICATIONS

Input voltage 100 V

Output voltage 100 - 70 - 50 - 35 - 25 - 0 V

Max. power 40 W

Attenuation 0 dB - 3 dB - 6 dB - 9 dB - 12 dB - OFF

Selector weight ca. ca 40 g

Transformer weight 200 g