Marantz PM 78 Manual

The Marantz PM 78 is a high-performance stereo integrated amplifier featuring advanced audio circuitry, multiple input options, and premium build quality. With 70 watts per channel into 8 ohms, this amplifier delivers exceptional sound quality for audiophiles and music enthusiasts. Below are key sections covering features, installation, operation, specifications, 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: High-current power amplifier, Phono input, Multiple line inputs, Tape monitor, Headphone output, Speaker selector.

Feature	Description
Power Output	70W + 70W (8Ω, 20Hz-20kHz)
Phono Input	MM/MC cartridge compatible
Input Selector	Phono, CD, Tuner, Aux, Tape
Headphone Jack	6.3mm stereo headphone output
Tape Monitor	Tape recording and playback
Speaker Selector	A/B speaker switching
Tone Controls	Bass and treble adjustment
Loudness Control	Enhanced bass at low volumes
Power Switch	Main power on/off
Volume Control	Motorized volume knob

Installation

Unpack and inspect contents. Place on stable, level surface with adequate ventilation.

Connect speakers: Use high-quality speaker cables to connect to Speaker A/B terminals.
Connect audio sources: Use appropriate cables for Phono, CD, Tuner, Aux inputs.
Connect tape deck: Use Tape In/Out jacks for recording and playback.
Plug into AC power outlet.

WARNING! Ensure proper ventilation around amplifier. Do not block ventilation openings.

First-Time Setup

Power on amplifier; follow proper startup procedure.

Speaker connection: Connect speakers to appropriate terminals (A or B).
Input selection: Rotate input selector to desired source (Phono, CD, etc.).
Volume adjustment: Start with volume at minimum, then gradually increase.
Tone controls: Set bass and treble to neutral position initially.

CAUTION! Always turn volume to minimum before powering on or changing inputs.

Specifications

Power Output: 70W + 70W (8Ω, 20Hz-20kHz)
Total Harmonic Distortion: 0.02% (20Hz-20kHz)
Frequency Response: 5Hz-50kHz (+0/-3dB)
Input Sensitivity: Phono: 2.5mV, Line: 150mV
Signal-to-Noise Ratio: Phono: 80dB, Line: 100dB
Tone Control: Bass: ±10dB at 100Hz, Treble: ±10dB at 10kHz
Power Requirements: 120V AC, 60Hz, 250W
Dimensions: 440mm (W) × 130mm (H) × 350mm (D)
Weight: 8.5kg

Controls and Settings

Front panel controls: Power switch, Input selector, Volume control, Tone controls, Loudness switch, Speaker selector, Headphone jack.

Rear panel: AC power input, Speaker terminals, Input jacks, Tape monitor jacks, Phono ground terminal.

Input Selection: Phono, CD, Tuner, Aux, Tape. Tone Control: Bass and treble adjustment (±10dB). Loudness: Compensates for human hearing at low volumes. Speaker Selection: A/B speakers or both. Volume: Motorized control with smooth operation.

Connecting Devices

Multiple input options: Phono, CD, Tuner, Aux, Tape.

Turn off amplifier before making connections.
Use high-quality interconnects for best performance.
Connect turntable to Phono input with ground wire.
Connect CD player to CD input using RCA cables.
Connect tape deck to Tape In/Out jacks.

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

Operation Guide

Daily operation procedures for optimal performance.

Power on: Turn on power switch; wait for protection circuit to engage.
Source selection: Rotate input selector to desired source.
Volume adjustment: Use volume control to set listening level.
Tone adjustment: Adjust bass and treble to personal preference.
Speaker selection: Choose A, B, or both speaker sets.
Tape monitoring: Use Tape Monitor for recording and playback.
Headphone use: Connect headphones to front panel jack.

WARNING! Do not operate with covers removed. High voltages present inside.

Maintenance

Unplug before cleaning. Use soft, dry cloth for exterior cleaning.

CAUTION! Do not use liquid cleaners or aerosols. Keep away from moisture and extreme temperatures.

Regulatory Information

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

Troubleshooting

Symptom	Possible Cause	Corrective Action
No sound from speakers	Speaker connections/volume	Check speaker wiring; ensure volume is up; verify input selection.
Distorted sound	Overload/settings	Reduce volume; check source level; verify tone control settings.
Hum or noise	Grounding/cables	Check phono ground connection; ensure proper cable routing.
One channel silent	Cable/connection issue	Check interconnects; verify balance control; test with different source.
Protection circuit active	Short circuit/overheating	Check speaker wires for shorts; allow unit to cool; reset power.

Service: Contact authorized Marantz service center for repairs.

Support: www.marantz.com