Marantz 4140 Manual

The Marantz 4140 is a professional stereo amplifier featuring 40 watts per channel, advanced tone controls, multiple input sources, and high-quality audio components. Designed for audiophiles and professional audio applications, it includes phono inputs, tape monitor, loudness control, and speaker selector options. 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. Operation Guide 8. Maintenance 9. Regulatory Information 10. Troubleshooting

Features at a Glance

Key components: Stereo amplifier with phono stage, tone controls, speaker selector, and multiple input sources.

Feature	Description
Power Output	40 watts per channel (8 ohms)
Input Sources	Phono, Tuner, Aux, Tape 1, Tape 2
Tone Controls	Bass, Midrange, Treble with defeat switch
Speaker Selector	A/B speaker outputs with independent switching
Loudness Control	Compensates for low volume listening
Tape Monitor	Dual tape loops for recording and playback
Headphone Jack	Front panel 1/4" stereo headphone output
Power Switch	Main power on/off with indicator light
Volume Control	Dual concentric knobs for balance and volume
Protection Circuit	Overload and thermal protection

Installation

Unpack and inspect contents. Place on stable, well-ventilated surface.

Connect speakers: Use speaker wire to connect to A/B speaker terminals.
Connect audio sources: Use RCA cables for phono, tuner, aux, and tape inputs.
Connect AC power: Plug into appropriate AC outlet.
Ground connection: Connect ground wire from turntable to ground terminal.

WARNING! Ensure proper ventilation; do not block cooling vents. Use correct speaker impedance.

First-Time Setup

Power on amplifier; verify all connections are secure.

Select input source: Turn selector knob to desired input (Phono, Tuner, Aux).
Adjust volume: Start with volume at minimum, gradually increase to desired level.
Set tone controls: Adjust bass, midrange, treble to preference.
Speaker selection: Choose A/B speakers using selector switch.

CAUTION! Always turn volume to minimum before powering on/off to prevent speaker damage.

Specifications

Power Output: 40 watts per channel (8 ohms, 20Hz-20kHz)
Total Harmonic Distortion: 0.08% at rated power
Frequency Response: 10Hz-50kHz (+0/-3dB)
Input Sensitivity: Phono: 2.5mV, Aux/Tuner: 150mV
Signal-to-Noise Ratio: Phono: 76dB, Aux: 90dB
Tone Control Range: Bass: ±10dB at 100Hz, Treble: ±10dB at 10kHz
Power Requirements: 120V AC, 60Hz, 200W
Dimensions: 17" W × 5" H × 12" D
Weight: 22 lbs

Controls and Settings

Front Panel: Power switch, Input selector, Volume/Balance, Tone controls, Loudness, Speaker selector.

Rear Panel: Input jacks, Speaker terminals, AC power, Ground terminal.

Tone Controls: Bass (±10dB at 100Hz), Midrange (±8dB at 1kHz), Treble (±10dB at 10kHz). Input Selection: Phono (MM), Tuner, Aux, Tape 1, Tape 2. Speaker Selection: A/B speakers with independent switching. Loudness: Compensates for Fletcher-Munson curve at low volumes.

Connecting Devices

Phono: Connect turntable to Phono inputs with ground wire. Tuner: Connect FM/AM tuner. Aux: Connect CD player, tape deck, or other line-level sources.

Turn off amplifier before making connections.
Match left/right channels (white/red RCA connectors).
Ensure proper grounding for phono inputs.
Use appropriate speaker wire gauge for speaker connections.

Tip: Keep audio cables away from power cords to minimize interference.

Operation Guide

Supports various audio sources with precise tone control.

Power on: Turn power switch; indicator light should illuminate.
Select source: Choose Phono, Tuner, Aux, or Tape inputs.
Adjust volume: Use volume control; balance with concentric knob.
Tone adjustment: Set bass, midrange, treble to preference.
Loudness: Engage for enhanced bass at low volumes.
Speaker selection: Choose A, B, or both speaker sets.
Tape monitoring: Use tape monitor for recording/playback.
Headphone use: Plug headphones to mute speaker output.

WARNING! Do not operate without proper load on speaker outputs. Avoid extreme volume settings.

Maintenance

Unplug before cleaning. Use soft, dry cloth for exterior; compressed air for controls.

CAUTION! Do not use liquids or solvents. Service by qualified personnel only.

Regulatory Information

FCC Part 15: Class B digital device; complies with interference limits. UL listed for safety. Copyright © Marantz; all rights reserved. For technical support, contact authorized Marantz service centers or visit www.marantz.com.

Troubleshooting

Symptom	Possible Cause	Corrective Action
No sound	Power/speaker connections	Check power cord; verify speaker connections; ensure volume up.
Distorted sound	Overload/incorrect settings	Reduce volume; check input levels; verify speaker impedance.
Hum or noise	Grounding/cable issues	Check ground connections; ensure proper cable routing.
One channel silent	Balance/cable issues	Adjust balance control; check RCA cables; swap channels.
Protection circuit active	Overload/short circuit	Check speaker wires for shorts; allow unit to cool.

Reset: Power cycle unit if protection circuit engages.

Service: Contact authorized Marantz service center for repairs.