DAYTON AUDIO A400 Stereo Power Amplifier User Manual

: June 1, 2024
: DAYTON AUDIO

Table of Contents

DAYTON AUDIO A400 Stereo Power Amplifier
Product Information
Product Usage Instructions
Features
What’s in the Box
Installing the Amplifier
Installing the Amplifier
Controls and Functions
Connections
Connecting Sources
Rear Panel Controls
Troubleshooting
Dimensions
Specifications
References
Read User Manual Online (PDF format)
Download This Manual (PDF format)

DAYTON AUDIO A400 Stereo Power Amplifier

DAYTON-AUDIO-A400-Stereo-Power-Amplifier-product

Product Information

Specifications

Class: A/B
Output Power: Pure Class A/B output power
Configuration: Stereo and bridged
Features: Auto-ON, external 12V trigger modes

Product Usage Instructions

Unpacking and Installation

Unpack the amplifier and inspect for shipping damage.
Retain all packing materials for potential future transport needs.
Install the amplifier in a standard 19-inch rack or on a stable surface using the included rack mounting kit.

Proper Cooling

Maintain a minimum of 2 inches of clearance on the top and sides of the amplifier during operation.
Leave 2 open rackspaces above the amplifier if installed in an equipment rack to ensure proper airflow.

Controls and Functions

Front Panel

POWER SWITCH: Turns the device on and off.
POWER/STANDBY/PROTECTION INDICATOR: Blue when on, red in standby or clipping.
VOLUME CONTROL: Adjusts speaker output (does not control thru outputs).

Rear Panel

LINE INPUT/OUTPUT SECTION: Connect audio sources here.
STEREO/BRIDGE MODE SWITCH: Select stereo or bridge mode.
ON MODE SELECTION: Choose operating mode.
12V TRIGGER CONNECTIONS: Connect external trigger.
FRONT LED ON/OFF SWITCH: Disable front panel lights in low light environments.
SPEAKER OUTPUTS: Connect speakers with consistent polarity.

Frequently Asked Questions (FAQ)

Q: What should I do if I notice shipping damage on my A400 amplifier?
A: Promptly inform the shipping company to initiate a claim. Retain all packing materials for inspection.
Q: How should I connect my audio sources to the A400?
A: Connect your audio sources to the LINE INPUT/OUTPUT SECTION on the rear panel of the amplifier.
Q: Can I disable the front panel lights on the A400?
A: Yes, you can use the FRONT LED ON/OFF SWITCH to turn off all front panel lights, including indicators.

Welcome
Thank you for purchasing the Dayton Audio A400 Amplifier. This amplifier has been designed to provide nothing but pure Class A/B output power for use with your favorite speakers. Capable of stereo and bridged configuration the A400 can easily integrate into any setup with built-in Auto-ON and external 12V trigger modes. We hope you enjoy listening to your new A400 as much as we have enjoyed designing it.

Features

160 watts per channel into 8Ω, 20-20kHz at 0.1% THD with 2 channels driven
300 watts per channel into 4Ω, 20-20kHz at 0.1% THD with 2 channels driven
High-current Class A/B amplifier design
Balanced (XLR) and unbalanced (RCA) inputs for each channel with dedicated thru outputs
Full range frequency response 20-20kHz
Large front volume knob for easy level control
Auto-ON and 12V remote trigger modes or complete control and integration
Front panel indicator can be turned off for use in low light environments
Rack mount installation kit included
Rear-panel dual voltage switch (115 and 230 volts)

What’s in the Box

A400 Amplifier
Rack Mounting Kit
Power Cable
This Manual

Installing the Amplifier

Unpacking
Please unpack your amplifier and carefully examine it for any potential damage that may have happened during shipping. In case you do discover any damage, it is important to promptly inform the shipping company.
While Dayton Audio is available and willing to assist as necessary, only the recipient can initiate a claim for any shipping related damage, If the product shows visible signs of damage upon arrival, be sure to retain the shipping carton for the shipper’s inspection.
We strongly advise you to keep all the packing materials, as they may be useful in the event you need to transport the unit in the future. Never attempt to ship the unit without the original factory carton and the accompanying packing materials.

Additional Materials
For installation, the following materials might be required and are not supplied in the package

Input cables
Output cables
Phillips screwdriver
Rack or stable surface for mounting the amplifier

Installing the Amplifier

CAUTION: Disconnect the A400 from any power source before beginning installation.
The A400 can be installed in any standard 19″ rack enclosure or on a stable surface or shelf. For rack installation please use the included rack mounting kit.

$DAYTON-AUDIO-A400-Stereo-Power-Amplifier- $1$$

Proper Cooling
Anytime the A400 is in use, there should be a minimum of 2″ of clearance on the top and sides of the amplifier. When installed in an equipment rack leave 2 open rackspaces above the amplifier to increase airflow in and around the amplifier. (Do not close the open rackspace with panels as this will reduce airflow.)

Controls and Functions

POWER SWITCH
Turns the device on and off.
POWER/STANDBY/PROTECTION INDICATOR
The ring surrounding the power switch will illuminate blue when the amplifier is on. It will also illuminate red when in standby or to indicate amplifier clipping.
VOLUME CONTROL
Turn this to control the output to your speakers. This volume knob does not control the thru outputs.

$DAYTON-AUDIO-A400-Stereo-Power-Amplifier- $2$$

LINE INPUT/ OUTPUT SECTION
Connect any audio sources here (pg. 7)
STEREO/BRIDGE MODE SWITCH (pg. 9)
ON MODE SELECTION (pg. 10)
12V TRIGGER CONNECTIONS (pg. 10)
FRONT LED ON/OFF SWITCH
The power indicator light on the front can be turned off when the A400 is installed in low light environments like near your TV. This switch will disable all lights on the front of the amplifier including standby and protection indicators
SPEAKER OUTPUTS
Using insulated two conductor wire to connect to speakers. The polarity, positive (+), and negative (-) for all speaker and amplifier connections must be consistent so both the left and right speakers are in phase.
AC VOLTAGE SELECTOR SWITCH
The unit is set at the factory for 110V operation. For 220V operation, move the voltage selector switch to the 220V position. When operating at 220V, the internal fuse located in the IEC socket should also be changed. In most 220V applications, a separate power cord will be required and is not included.
AC POWER INPUT $DAYTON-AUDIO-A400-Stereo-Power-Amplifier- $3$$

Connections

Connecting to Mains Power
Before connecting the main power cable, make sure that the voltage selector switch is set according to your local voltage. Incorrect setting of the voltage selector switch could cause damage to the amplifier and has a potential risk of fire. $DAYTON-AUDIO-A400-Stereo-Power-Amplifier- $4$$

Power Up Procedure
Follow these steps when powering on the amplifier for the first time.

Ensure all connections except for the power cord are disconnected.
Press the amplifier’s front power button. If the front LED ON/OFF switch is set to ON and proper mains power is provided the amplifier will turn on and the front power indicator will illuminate blue.
Turn off the amplifier, turn the volume knob all the way down and make all necessary connections as described Connections Sources and Connecting Outputs (pg. 6-8)
Once all connections have been made, turn on the amplifier.
Set all connected audio sources to their optimal level and begin playing audio to the amplifier.
Turn the amplifier’s volume control up until the desired loudness is achieved.

NOTE: Always turn the amplifier on last and off first to avoid accidental output to any connected speakers; potentially damaging the speakers.

Connecting Sources

Unbalanced RCA Input
Unbalanced RCA Output
Balanced XLR Input
Balanced XLR Output
Balanced/Unbalanced Selection Switch

Each input section on the amplifier can accept balanced (XLR) or unbalanced (RCA) line level signals. Using high quality cables will ensure the best possible transmission from your connected devices.
Selection between balanced and unbalanced inputs can be performed on a per channel basis to allow for different connections to different channels.
The balanced and unbalanced outputs will pass audio from their respective inputs. They are not affected by the input selection switch or the front volume control.

Connecting Outputs

Stereo Operation $DAYTON-AUDIO-A400-Stereo-Power-Amplifier- $6$$

In stereo operation, the A400 can power speakers with a minimum impedance of 4Ω. Using high quality two conductor speaker wire connect your speakers to the binding posts on the rear of the unit.
Connect the A400’s left speaker terminals marked “L-” and “L+” to the corresponding “-” and “+” terminals on your left speaker. Repeat the same process for the right channel.

Connecting Banana Plug Cables

Tighten the knob.
Insert the banana plug terminated cable into the end of the corresponding terminal.

Connecting Speaker Wires

Strip about 3/8″ of insulation from the end of each speaker wire and twist the bare wires of the cable together.
Unscrew the knob before inserting the bare wire into the hole in the side of each terminal before tightening the knob to secure the wire.

$DAYTON-AUDIO-A400-Stereo-Power-Amplifier- $8$$

Bridged Operation

$DAYTON-AUDIO-A400-Stereo-Power-Amplifier- $9$$

In bridged mode, the A400 can power a speaker with a minimum impedance of 8Ω. Using high quality two conductor speaker wire, connect a speaker to the bridged output binding posts on the rear of the unit. Observe the proper polarity of the bridged outputs.
The bridged output will only bass audio from the left channel input. The A400 is not designed to sum the two input channels to mono.

Rear Panel Controls

The A400 has three different modes for turning the amplifier on and off. AUTO ON will automatically detect audio on the inputs and place the amplifier is standby when not in use, 12V TRIGGER which will turn the amplifier on and off when an external device sends a dedicated control signal to the amplifier, and ON which is the normal operation.

Auto On
For ultimate control in any installation, the A400 has an auto sensing function that can turn off the amplifier when not in use and turn it back on when audio is detected. The A400’s standby mode is indicated by a red power indicator. To use auto sensing, set the ON MODE switch to AUTO; for normal operation, set it to ON.
The A400 will enter standby after fifteen minutes of silence and will turn back on when music is played again. Once audio is sensed, the power indicator light will change back to blue to indicate that the amplifier is on.

Remote Trigger
The 12V TRIGGER mode functions similar to the AUTO ON mode except that on and standby are controlled by a 12V signal received on the 12V IN connection on the rear of the amplifier. When a 12V signal is present, the A400 will be active and enter standby when the signal is disabled.
All connections should be made with 3.5mm unbalanced cables.

The 12V OUT connection is not controlled by the A400. It only serves to duplicate the signal received on the 12V IN connection.

System Protection
The A400 is equipped with triple failsafe protection to ensure self-protection as well as the protection of other connected devices.
Self-locking power stage: if a short on the AC side of the power supply is detected, the DC side of the power supply will meet the bias voltage of the Collector/Emitter junction, disallowing signal amplification to occur.
Temperature monitoring: Thermistor heat monitoring constantly measures the temperature of the heat sinks. When this protection is tripped, the thermistor will allow current to flow, opening the protection circuit.
Short circuit protection: when zero resistance across the output terminals is detected, similar to the self-locking feature, the DC power supply will meet the bias voltage of the Collector/Emitter junction, disallowing signal amplification to occur.

Troubleshooting

Problem| Cause| Solution|
---|---|---|---
The Unit fails to turn on| The power cable is not connected| Check to make sure both ends of the power cable are connected|
| properly| properly.|
| Incorrect voltage selection switch| Verify that the voltage selection switch is set according the region|
| setting| and power standard in your country.|
| Protection circuit has been activated| Turn the amplifier off and check that your speaker wires are not|
| | shorting out. If this problem persists please contact Dayton Audio|
| | for customer support.|
| The internal fuse has been tripped| Replace the internal fuse with the proper rating for your region.|
| | (p.5)|
The unit turns off| There is a short in the connected| Examine the speaker wire for any damage. Do not use any cable|
suddenly| speaker wire.| that has exposed wire.|
| Speaker malfunctioning| Disconnect the speakers one at a time to see if the issue is caused|
| | by the speakers or the amplifier. If the problem persists with all|
| | speakers please contact Dayton Audio customer support.|
No sound| The amplifier is in standby mode| Verify the proper position of the On Mode Selection Switch. If set|
| | to 12V trigger, there must be a signal present on the 12V Trigger|
| | Input to activate the amplifier (p.10)|
| Correct input has not been selected| Verify that the Balanced/Unbalanced Selection Switch is set to the|
| | proper input.|
| Incorrect cable connections| Double check that the device that you are trying to listen to is|
| | connected to the correct input.|
The sound is distorted| The output load is wired incorrectly| Stereo and bridged operation require different wiring|
| | configurations for the speaker outputs. Verify that the proper|
| | settings are enabled for the desired configuration. (p.8-9)|
| Impedance of connected speakers is| The Amplifier is capable of powering speakers as low as 4Ω in|
| too low| stereo mode and 8Ω in bridged mode. Verify that any connected|
| | speakers have impedances higher than this. (p.8-9)|
| The input signal is too high and is| Turn down the level of the source signal until the distortion is no|
| clipping the input of the amplifier| longer present.|
Low Volume| Volume on the playback device is| Verify that any volume control the connected preamplifier, mixer,|
| turned down| or playback device is turned up.|
The Sound output| The speakers polarity is reversed| Double check the speaker connections, ensuring that the + and –|
lacks Bass| | terminals are connected properly on both speakers. (p.9)|