Denon PMA 255 Service Manual

The Denon PMA 255 is a high-quality integrated amplifier designed to deliver exceptional audio performance. It features a robust power output, multiple input options, and advanced circuitry to ensure clear and dynamic sound reproduction. Below are key sections for safety, features, installation, setup, operation, and troubleshooting.

1. Features at a Glance 2. Installation 3. First-Time Setup 4. Specifications 5. Controls and Settings 6. Connecting Devices 7. Operating the Amplifier 8. Maintenance and Care 9. Regulatory Information 10. Troubleshooting

Features at a Glance

Key components: Integrated amplifier, multiple input options, tone control, headphone output, remote control.

Feature	Description
Power Output	High-quality sound with robust power delivery
Input Options	Multiple inputs for various audio sources
Tone Control	Adjustable bass and treble settings
Headphone Output	Dedicated output for private listening
Remote Control	Convenient control from a distance

Installation

Unpack and inspect contents. Place the amplifier on a stable surface.

Connect audio sources: Use RCA cables for input connections.
Connect speakers: Ensure correct polarity when connecting speaker wires.
Plug into AC power.

WARNING! Amplifier can get hot; ensure proper ventilation.

First-Time Setup

Power on the amplifier; follow the setup instructions.

Select input source: Use the INPUT button on the remote.
Adjust volume: Use the volume knob or remote control.
Set tone controls: Adjust bass and treble as desired.

CAUTION! Ensure all connections are secure before powering on.

Specifications

Power Output: 50W per channel (8 ohms).
Frequency Response: 10 Hz - 100 kHz.
Input Impedance: 47 kΩ.
Signal-to-Noise Ratio: 100 dB.
Dimensions: 440 x 370 x 150 mm.
Weight: 8 kg.
Power Supply: AC 120V, 60Hz.

Controls and Settings

Access controls via front panel or remote. Key controls include POWER, INPUT, VOLUME, and TONE.

Remote: POWER, INPUT selection, VOLUME control, MUTE.

Connecting Devices

Connect audio sources using RCA cables. Ensure all connections are secure.

Turn off the amplifier before connecting devices.
Match cables to ports correctly.
Select the appropriate input source on the amplifier.

Tip: Use high-quality cables for optimal sound quality.

Operating the Amplifier

Power on the amplifier and select the desired input source. Adjust volume and tone settings as needed.

Maintenance and Care

Unplug before cleaning. Use a dry cloth to clean the exterior; avoid liquids.

CAUTION! Do not expose to moisture or extreme temperatures.

Regulatory Information

This device complies with FCC Part 15 regulations. For support, visit www.denon.com or contact customer service.

Troubleshooting

Symptom	Possible Cause	Corrective Action
No sound	Incorrect input/source	Check input selection and connections.
Distorted sound	Overdriven volume	Reduce volume and check speaker connections.
Remote not working	Batteries	Replace batteries in the remote control.
Amplifier overheating	Poor ventilation	Ensure proper airflow around the amplifier.

Reset: Unplug for 10 seconds to reset.

Service: Contact Denon support for further assistance.