Marantz Model SR-68 Manual

The Marantz Model SR-68 is a high-performance stereo receiver featuring AM/FM tuner, multiple audio inputs, phono input for turntables, tape monitor, loudness control, and speaker outputs. With 50 watts per channel RMS power output, this classic receiver delivers exceptional audio quality for home stereo systems. Below are key sections for 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 Components 7. Tuner Operation 8. Audio Adjustments 9. Care & Maintenance 10. Regulatory Information 11. Troubleshooting

Features at a Glance

Key components: Stereo amplifier, AM/FM tuner, Input selector, Tone controls, Loudness switch, Tape monitor, Speaker outputs.

Feature	Description
Power Output	50 watts per channel RMS (8 ohms)
Tuner Section	AM/FM stereo with signal strength meter
Input Selector	Phono, Aux, Tape 1, Tape 2
Tone Controls	Bass and Treble adjustment
Loudness Control	Compensates for low volume listening
Tape Monitor	Allows tape recording and playback
Speaker Selector	A/B speaker system selection
Headphone Jack	For private listening
Power Switch	Main power on/off with indicator light
Volume Control	Master volume adjustment

Installation

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

Connect speakers: Use speaker wire to connect to A or B speaker terminals.
Connect audio sources: Phono for turntable, Aux for CD player, Tape for cassette deck.
Connect antenna: FM antenna to FM terminals, AM antenna to AM terminals.
Plug into AC power outlet.

WARNING! Ensure proper ventilation; do not block ventilation openings. Use correct speaker impedance (8 ohms recommended).

First-Time Setup

Power on receiver; set initial controls to neutral positions.

Set input selector: Choose appropriate source (Phono, Aux, etc.).
Adjust volume: Start at minimum, gradually increase to desired level.
Tune FM stations: Use tuning dial and signal strength meter for best reception.
Set tone controls: Begin with flat response (12 o'clock position).
Select speakers: Choose A or B speaker system as needed.

CAUTION! Always turn volume down before switching inputs or powering off.

Specifications

Power Output: 50 watts per channel RMS at 8 ohms
Frequency Response: 20Hz - 20kHz (±1dB)
Total Harmonic Distortion: Less than 0.1%
Input Sensitivity: Phono: 2.5mV, Aux: 150mV
Signal-to-Noise Ratio: Phono: 70dB, Aux: 90dB
Tuner Section: FM stereo, AM broadcast
Power Requirements: 120V AC, 60Hz
Dimensions: Standard component width (17 inches)
Weight: Approximately 25 lbs

Controls and Settings

Front Panel: Power switch, Input selector, Volume, Balance, Bass, Treble, Loudness, Speaker selector, Tuning dial, Signal meter.

Rear Panel: Speaker terminals, Input jacks, Antenna terminals, AC power cord, Fuse holder.

Input Selection: Phono (turntable), Aux (CD/tuner), Tape 1, Tape 2. Tone Controls: Bass (±10dB at 100Hz), Treble (±10dB at 10kHz). Loudness: Enhances bass at low volumes. Balance: Adjusts left/right channel balance. Speaker Selector: A, B, A+B, or off.

Connecting Components

Speaker Connections: A and B speaker terminals. Audio Inputs: Phono, Aux, Tape 1, Tape 2. Antenna Connections: FM 75 ohm, AM antenna.

Turn off power before making connections.
Connect speakers observing correct polarity (+/-).
Use RCA cables for audio inputs.
Connect FM antenna for best reception.
Ensure all connections are secure.

Tip: Use high-quality cables for best audio performance.

Tuner Operation

AM/FM stereo tuner with manual tuning and signal strength indicator.

Select Tuner input: Set input selector to appropriate position.
Tune stations: Rotate tuning dial while watching signal meter.
FM stereo: Stereo indicator lights when receiving stereo broadcast.
AM broadcast: Rotate AM antenna for best reception.
Fine tuning: Adjust for clearest sound and strongest signal.

WARNING! Do not force tuning dial; turn gently for precise station selection.

Audio Adjustments

Tone Controls: Bass and treble adjustment. Loudness: Compensates for Fletcher-Munson curves. Balance: Left/right channel balance.

Recommended Settings: Start with tone controls at neutral, adjust to room acoustics and personal preference. Use loudness control for low-volume listening.

Care & Maintenance

Unplug before cleaning. Use soft, dry cloth for exterior. Clean controls with appropriate contact cleaner if needed.

CAUTION! Do not use liquids or solvents on controls or finish. Keep away from moisture and extreme temperatures.

Regulatory Information

FCC Part 15: Class B digital device compliant. Manufactured to meet industry standards for home audio equipment. Copyright © Marantz. For service and support, contact authorized Marantz service centers.

Troubleshooting

Symptom	Possible Cause	Corrective Action
No sound from speakers	Speaker connections/selector	Check speaker wires; verify speaker selector position
Distorted sound	Overload/incorrect settings	Reduce volume; check input levels; verify tone settings
Poor FM reception	Antenna connection	Check FM antenna; reposition for better reception
Hum or noise	Grounding issues	Check ground connections; separate from power cables
One channel silent	Balance control/cables	Check balance setting; verify RCA cable connections

Service: Contact authorized Marantz service center for internal repairs.