Audio T Verdict
The Arcam PA240 is a powerful and unusually flexible two-channel power amplifier for serious stereo systems, demanding loudspeakers and high-performance home cinema installations.
In its standard stereo configuration, it delivers 225W per channel into 8 ohms and 380W per channel into 4 ohms. Arcam's Class G architecture provides a substantial 50W Class A operating region before calling on the additional power supply when musical peaks demand more output.
Switchable RCA and balanced XLR inputs, selectable gain, bridged mono operation, dual-mono bi-amping, trigger control and network automation make the PA240 considerably more adaptable than a conventional stereo power amplifier.
It requires a suitable pre-amplifier, streaming pre-amplifier or AV processor because it contains no volume control, source selection, DAC, phono stage or music streamer. It also needs proper ventilation and careful configuration, particularly in bridged or dual-mono operation. Correctly matched and installed, however, the PA240 provides substantial power, control and upgrade potential.
Arcam PA240 Class G Power Amplifier
The Arcam PA240 is a two-channel Class G power amplifier designed for high-performance stereo systems and home cinema installations.
It receives a variable line-level signal from a pre-amplifier, streaming pre-amplifier, integrated amplifier with pre-out sockets or AV processor and provides the current and power required to drive passive loudspeakers.
In standard stereo operation, one PA240 powers the left and right loudspeakers. It can also be configured as a high-output bridged mono amplifier or used as part of a two-amplifier dual-mono and bi-amped system.
A Pre-Amplifier or AV Processor Is Required
The PA240 does not provide source selection or listening-volume control.
It must receive a controlled variable-level signal from a suitable pre-amplifier, processor, streamer with pre-amplifier output or integrated amplifier with compatible pre-out sockets.
Arcam Class G Amplification
Class G amplification is designed to combine the low-level refinement associated with Class A operation with the greater efficiency and power of a multi-rail amplifier.
Arcam specifies 50W of Class A operation for the PA240. At lower and moderate output levels, the amplifier uses its lower-voltage supply region. When the music requires greater power, an additional supply rail is brought into operation.
This approach allows the amplifier to provide substantial output without requiring the entire circuit to operate continuously at the temperature and power consumption of a comparably powerful conventional Class A design.
Read more about Arcam's amplifier design in our
Audio T guide to Arcam streaming and Class G amplification
.
225W per Channel into 8 Ohms
With both channels operating across the full 20Hz to 20kHz audio range, the PA240 delivers 225W per channel into an 8-ohm loudspeaker load at the manufacturer's stated 0.2% distortion condition.
This provides considerably more output than a typical integrated amplifier and makes the PA240 a suitable candidate for larger rooms, higher listening levels and loudspeakers that benefit from a powerful amplifier.
Greater amplifier power does not simply mean greater volume. Adequate power and current can also help maintain control of the speaker drivers during complex or dynamic musical passages.
380W per Channel into 4 Ohms
Output increases to 380W per channel into a 4-ohm load, demonstrating the amplifier's ability to provide additional current when the loudspeaker impedance becomes more demanding.
A nominal impedance figure does not tell the whole story, however. Many loudspeakers fall below their stated impedance at particular frequencies and may also present difficult electrical phase angles.
Speaker sensitivity, impedance behaviour, room size, listening distance and preferred volume should therefore all be considered before choosing an amplifier.
Our
amplifier and loudspeaker matching guide
explains why watts and nominal impedance are only part of the picture.
Toroidal Power Supply
A substantial toroidal transformer provides the electrical foundation for the PA240's high-output amplifier stages.
Toroidal transformers can provide strong current delivery while helping to limit stray magnetic fields within the amplifier when they are correctly designed and installed.
The power supply is partnered with parallel output transistors, allowing each channel to share the electrical and thermal demands placed on the amplifier during high-level operation.
Acoustically Damped Chassis
The internal electronics are housed within a rigid, acoustically damped HDA-series chassis.
The substantial enclosure helps support the heavy transformer, output devices, heat management and speaker connections while reducing the effect of unwanted mechanical vibration.
At 18kg, the PA240 requires a stable equipment rack or shelf with sufficient load capacity.
Standard Stereo Operation
Stereo mode is the most straightforward configuration and uses the two internal amplifier channels to power the left and right loudspeakers.
A stereo pre-amplifier output connects to the PA240 through either RCA or balanced XLR cables, and the rear mode switch is set to its standard stereo position.
The left and right loudspeakers then connect to their corresponding positive and negative speaker terminals.
Switch Off Before Changing Connections or Modes
Switch the PA240 and connected pre-amplifier off before changing interconnects, speaker cables, input type, gain or operating mode.
Changing wiring or rear-panel switches while the system is powered can produce damaging noises or incorrect amplifier operation.
790W Bridged Mono Operation
The PA240 can combine its two internal channels to provide a single high-power output rated at 790W into 8 ohms.
A complete stereo bridged system therefore requires two PA240 amplifiers, with one amplifier powering the left speaker and the second powering the right.
Only the left input is used on each amplifier in this configuration, and Arcam recommends the 25dB gain setting for bridged operation.
Bridged Wiring Must Be Followed Exactly
Bridged operation uses the positive L+ and R+ speaker terminals. The negative L- and R- terminals must not be connected.
Incorrect bridged wiring can severely damage the amplifier. Follow the Arcam manual precisely or ask Audio T to configure the system.
Check Loudspeaker Suitability Before Bridging
Bridging changes the electrical load seen by each internal amplifier channel and is not appropriate for every loudspeaker.
Confirm the speaker impedance and amplifier requirements before using bridged mono operation.
Dual-Mono and Bi-Amped Operation
Two PA240 amplifiers can also be configured in dual-mono mode to bi-amplify a compatible pair of loudspeakers.
In this arrangement, one PA240 is dedicated to each speaker. One internal amplifier channel drives the low-frequency terminals while the other drives the high-frequency terminals.
Arcam specifies the 31dB gain position and dual-mono mode setting for this configuration.
Remove the Loudspeaker Jumper Links
A bi-wireable loudspeaker normally has metal links joining its high-frequency and low-frequency terminals.
These links must be removed before active bi-amping. Leaving them fitted can connect the amplifier channels together and cause serious damage.
Two PA240 Amplifiers Are Required
Arcam's PA240 dual-mono arrangement uses one complete PA240 for each loudspeaker.
It is not the same as ordinary bi-wiring from a single stereo amplifier.
Switchable RCA Inputs
A stereo pair of unbalanced RCA inputs provides compatibility with conventional pre-amplifiers, AV processors and streamers.
RCA input sensitivity is specified as 1.15V RMS for 200W output into 8 ohms.
Use well-screened analogue interconnects and keep them reasonably short, particularly where the system contains high-current mains and speaker cables.
Balanced XLR Inputs
Balanced XLR inputs are provided for pre-amplifiers and processors with compatible balanced outputs.
XLR input sensitivity is specified as 2.3V RMS for 200W output into 8 ohms.
A balanced connection can provide improved rejection of interference, particularly with long cable runs or equipment installed in an electrically busy home cinema or custom-installation system.
Select the Correct Input Type
The rear input switch must match the connection being used.
Select RCA for the unbalanced phono inputs or XLR for the balanced inputs. The two input types are alternatives and should not be used simultaneously for the same channel.
25dB and 31dB Gain Settings
A rear-panel switch provides a choice of 25dB or 31dB amplifier gain.
Gain determines how much input voltage is required to reach a given output level. It is not a second volume control and does not alter the amplifier's maximum rated power.
The setting can help the PA240 integrate with pre-amplifiers, AV processors and other power amplifiers with different output levels and gain structures.
Arcam recommends 25dB for bridged operation and specifies 31dB for its dual-mono bi-amping arrangement.
Match Gain Carefully in Home Cinema Systems
When the PA240 powers selected channels alongside another amplifier, an unsuitable gain setting may make those channels substantially louder or quieter before calibration.
Select the appropriate gain before running the AV processor's channel-level or room-correction setup.
Passive RCA Loop Outputs
The OUT L and OUT R sockets provide passive copies of the signals received through the corresponding RCA inputs.
These outputs can pass the RCA signal to another suitable amplifier or component without an additional active gain stage.
They are not volume-controlled pre-amplifier outputs, and no additional filtering or amplification is applied.
The Loop Outputs Work Only with RCA Input
The OUT L and OUT R sockets copy signals received through the RCA inputs.
They do not provide looped copies of signals connected through the balanced XLR inputs.
Heavy-Duty Loudspeaker Terminals
Separate left and right binding posts accept suitable terminated speaker cable.
Correct polarity must be maintained throughout the system, with each positive amplifier terminal connected to the corresponding positive loudspeaker terminal.
Loose strands of bare cable can cause a short circuit between the terminals. Professionally terminated banana plugs or spade connectors can provide a safer and more reliable connection where compatible.
Consider the
Chord Company EpicX speaker cable
for a suitably specified high-performance system.
Protection and Status Indication
The PA240 monitors operating temperature, speaker short circuits and DC offset conditions.
The front indicator changes or flashes to help identify the type of protection event.
If protection is activated, switch the amplifier off, allow it to cool where necessary and check the loudspeaker cables and system connections before restarting it.
Do Not Repeatedly Reset a Fault
Repeatedly switching the amplifier back on without correcting a short circuit, overheating problem or other fault can risk further damage.
Disconnect the system and contact Audio T if the protection warning returns.
Stereo Hi-Fi System Integration
The PA240 can form the power-amplification stage of a conventional separate pre and power amplifier system.
A pre-amplifier or suitable streamer handles source selection and volume, while the PA240 is dedicated to driving the loudspeakers.
Separating the sensitive pre-amplifier circuitry from the high-current power stage can provide more physical space for each function and reduce the risk of interaction between them.
Our
guide to pre-amplifiers, power amplifiers and monoblocks
explains the main benefits and considerations.
Home Cinema System Integration
The PA240 can provide high-power amplification for the front left and right channels of a compatible home cinema system.
It can be connected to the pre-amplifier outputs of an AV receiver or processor, allowing the main stereo speakers to benefit from dedicated Class G amplification.
The PA240 may also be useful in larger custom systems where its trigger, Ethernet and RS232 connections can be integrated with compatible control equipment.
Browse our
home cinema amplifiers and AV receivers
for suitable processors and system options.
Partnering the ATC SCM40
The
ATC SCM40 floorstanding speakers
are one example of a revealing passive loudspeaker that can benefit from powerful, controlled amplification.
Their 85dB sensitivity and recommended amplifier range of 75W to 300W make careful amplifier matching worthwhile.
The PA240's stereo output is within that stated recommendation at 8 ohms, although the final choice should always be confirmed through a demonstration with the complete system.
Read our
Audio T SCM40 listening review
for more information about these speakers.
Ethernet and RS232 Control
An Ethernet connection and RS232 port allow compatible third-party control systems or computers to monitor and control the PA240.
These connections are intended for automation and custom installation rather than music streaming.
Network and RS232 functions are disabled in the lowest-power standby mode by default but can be enabled when remote wake-up and control are required.
Ethernet Is for Control, Not Music Streaming
The network connection does not turn the PA240 into a network music player.
A separate streamer, pre-amplifier or AV processor is required for source playback and volume control.
12V Trigger Input and Output
A trigger input allows a compatible pre-amplifier, AV processor or other control product to switch the PA240 between standby and operation.
A 12V trigger output rated at up to 100mA can control the power state of another compatible component.
Trigger operation can make a separates system behave more like a single integrated product by switching connected equipment on and off together.
Trigger Leads Are Not Supplied
Arcam specifies a mono 3.5mm trigger cable for compatible trigger connections.
Check the voltage, polarity and requirements of every connected product before making the connection.
USB Port for Software Updates
The rear USB connection is provided for amplifier software updates.
It is not a USB audio input and cannot receive music from a computer, phone, tablet or storage drive.
USB Audio Is Not Supported
Do not connect the PA240 to a computer expecting it to operate as a DAC or USB sound device.
Audio must enter through the RCA or balanced XLR analogue inputs.
Automatic Standby
The PA240 is configured to enter standby after an extended period without an audio signal or user interaction.
The default automatic standby period is 20 minutes and can be disabled or adjusted through the available control options.
Standby power consumption is specified at less than 0.5W when the lowest-power standby mode is used.
Ventilation and Placement
The PA240 is designed to run warm during normal operation and can generate significant heat when driving demanding loudspeakers at high levels.
Place it on a firm, level and stable surface with generous space around the ventilation openings.
Arcam recommends more than 300mm of clearance and advises against installing the amplifier in a closed cabinet without effective ventilation.
Do Not Stack Equipment on the PA240
Placing another component on top can obstruct airflow and expose that component to heat from the amplifier.
The equipment rack must also be capable of safely supporting the PA240's 18kg weight.
Keep Turntables Away from the Transformer
Do not place a turntable directly on top of or immediately beside the PA240.
Turntables and phono cartridges can pick up mechanical vibration and electromagnetic hum from large power supplies.
System Matching
Well Suited To
- High-performance stereo pre and power amplifier systems
- Demanding passive standmount and floorstanding speakers
- Larger listening rooms and higher listening levels
- Balanced pre-amplifiers using the XLR inputs
- Conventional pre-amplifiers using the RCA inputs
- Home cinema front left and right channel upgrades
- Bridged mono systems using two PA240 amplifiers
- Dual-mono bi-amped systems using two PA240 amplifiers
- Custom installations using Ethernet or RS232 control
- Systems requiring 12V trigger integration
Check Before Buying
- A suitable pre-amplifier or AV processor is required
- No listening-volume control
- No source selection
- No built-in DAC or digital audio input
- No phono stage
- No music streaming or Bluetooth
- Ethernet is for control rather than audio playback
- USB is for software updates only
- RCA loop outputs do not work with XLR input
- Bridged and bi-amped operation require careful configuration
- The amplifier weighs 18kg
- Substantial ventilation space is required
Connection Guidance
- Use RCA or XLR input, not both simultaneously
- Match the rear input switch to the chosen cable
- Select 25dB or 31dB gain to suit the system
- Switch everything off before changing modes
- Maintain correct loudspeaker polarity
- Use secure speaker-cable terminations
- Follow the manual exactly for bridged operation
- Remove speaker terminal links before active bi-amping
- Run AV calibration after setting amplifier gain
- Provide open space around the amplifier
Browse our
Hi-Fi amplifiers and power amplifiers
,
home cinema amplifiers and AV receivers
,
passive Hi-Fi speakers
and
interconnects and speaker cables
, or explore the complete
Arcam range at Audio T
.
PA240, PA410 and PA720 Comparison
Arcam PA240
- Two-channel Class G power amplifier
- 225W per channel into 8 ohms
- 380W per channel into 4 ohms
- 790W bridged mono output
- Stereo, bridged and dual-mono modes
- RCA and balanced XLR inputs
Arcam PA410
- Four-channel Class AB power amplifier
- Designed for multi-channel and custom systems
- RCA input and loop-output connections
- A more compact option for additional AV channels
View the Arcam PA410 power amplifier
Arcam PA720
- Seven-channel Class G power amplifier
- Designed for larger home cinema systems
- RCA and balanced XLR inputs
- Class G amplification across all seven channels
View the Arcam PA720 power amplifier
Finish
HDA Black
The PA240 uses Arcam's understated HDA-series black finish with a substantial full-width chassis and minimal front-panel controls.
Key Features
- High-performance two-channel power amplifier
- Arcam Class G amplifier architecture
- 50W Class A operating region
- 225W per channel into 8 ohms
- 380W per channel into 4 ohms
- 790W bridged mono output into 8 ohms
- Full rated power measured from 20Hz to 20kHz
- 0.001% harmonic distortion at 80% power and 1kHz
- Toroidal power transformer
- Parallel transistor output stages
- Acoustically damped HDA-series chassis
- Standard stereo operation
- Bridged mono operation
- Dual-mono bi-amplifier operation
- Switchable unbalanced RCA inputs
- Switchable balanced XLR inputs
- Selectable 25dB and 31dB amplifier gain
- Passive RCA loop outputs
- Heavy-duty loudspeaker binding posts
- Compatible with 4-ohm to 16-ohm speaker wiring
- Ethernet control connection
- RS232 control connection
- 12V trigger input
- 12V 100mA trigger output
- USB connection for software updates
- Automatic standby
- Less than 0.5W low-power standby consumption
- Temperature, short-circuit and DC-offset protection
- 18kg full-width construction
- HDA Black finish
Frequently Asked Questions
What is a power amplifier?
A power amplifier receives a controlled line-level signal from a pre-amplifier or processor and provides the power needed to drive passive loudspeakers.
Does the Arcam PA240 have a volume control?
No. Volume must be controlled by a separate pre-amplifier, streamer, integrated amplifier or AV processor.
Can I connect a CD player directly?
Only when another component provides safe volume control. A fixed-output CD player should not normally be connected directly because the PA240 has no volume control.
Can I connect a streamer directly?
Yes, provided the streamer has a suitable variable pre-amplifier output and its volume is initially set very low.
How powerful is the PA240 in stereo?
It delivers 225W per channel into 8 ohms and 380W per channel into 4 ohms across the 20Hz to 20kHz audio range.
What does Class G mean?
Class G uses more than one power-supply level. The amplifier operates in its lower-voltage region for ordinary signals and calls on the higher supply when additional output is required.
How much Class A operation does it provide?
Arcam lists 50W of Class A operation for the PA240.
Does it support balanced XLR connections?
Yes. It provides balanced left and right XLR inputs alongside conventional RCA inputs.
Can RCA and XLR be used at the same time?
No. Select the required input type using the rear switch and use either RCA or XLR for the system.
What do the 25dB and 31dB settings do?
They change the amplifier gain and therefore the input voltage needed to reach a particular output. They do not change the PA240's maximum rated power.
Can it be bridged?
Yes. Bridged mono mode provides 790W into 8 ohms. A stereo bridged system requires two PA240 amplifiers.
Can I bridge one PA240 and still run stereo speakers?
No. Bridging combines both internal channels into one mono output. Two amplifiers are required for bridged stereo.
Which speaker terminals are used in bridged mode?
Arcam specifies the L+ and R+ terminals. The L- and R- terminals must not be connected. Follow the manual exactly.
What is dual-mono mode?
In Arcam's PA240 arrangement, one complete amplifier is used for each bi-wireable speaker, with the internal channels driving its low-frequency and high-frequency terminals separately.
Can one PA240 bi-amplify both speakers?
Not in Arcam's specified dual-mono arrangement. Two PA240 amplifiers are required, one for each loudspeaker.
Do I remove the speaker jumper links when bi-amping?
Yes. The links joining the high-frequency and low-frequency terminals must be removed before active bi-amping.
What are the RCA output sockets for?
They provide passive looped copies of the signals connected to the RCA inputs. They are not controlled pre-amplifier outputs.
Do the RCA outputs copy the XLR inputs?
No. They copy only the corresponding RCA input signals.
Can the PA240 be used in a home cinema system?
Yes. It can power the front left and right speakers from the pre-out sockets of a compatible AV receiver or processor.
Does the Ethernet connection stream music?
No. Ethernet is provided for compatible automation, control and monitoring.
What is the RS232 connection for?
It allows a compatible computer or third-party home automation system to monitor and control the amplifier.
Does it have trigger control?
Yes. It has trigger input and a 12V trigger output rated at up to 100mA.
Can I play music through the USB socket?
No. USB is used only for software updates.
Does it enter standby automatically?
Yes. The default automatic standby period is 20 minutes without an input signal or user interaction. The function can be adjusted or disabled.
How much space does it need for ventilation?
Arcam recommends more than 300mm of clearance and advises against using a closed cabinet without effective ventilation.
Can another component be placed on top?
No. Equipment placed on top can obstruct the ventilation openings and be exposed to heat from the amplifier.
How heavy is the PA240?
It weighs 18kg, so a stable and suitably rated equipment rack is required.
Why Buy From Audio T?
- Demonstrations with suitable pre-amplifiers and loudspeakers
- Advice on whether your speakers require this level of power
- Stereo, bridged and dual-mono configuration guidance
- Safe bridged-mode speaker connection assistance
- Active bi-amplification setup and jumper-link guidance
- RCA and balanced XLR system matching
- 25dB and 31dB gain-setting advice
- Home cinema pre-out and channel-level setup
- Ethernet, RS232 and trigger integration guidance
- Speaker cable and interconnect recommendations
- Equipment rack, ventilation and installation advice
- Comparison with the Arcam PA410 and PA720
- Comparison with alternative stereo power amplifiers
- Home demonstrations may be available
- Part exchange available on suitable existing equipment
- Ongoing system, installation and setup support
Contact your local Audio T store
to arrange a demonstration or discuss integrating the Arcam PA240 into your stereo or home cinema system.