Marantz Model 2238B Manual

The Marantz Model 2238B is a classic stereo receiver from the 1970s featuring 38 watts per channel RMS power, high sensitivity FM/AM tuner, phono input for turntables, tape monitor circuits, loudness contour, bass and treble controls, and distinctive blue fluorescent tuning meter. This manual covers operation, connections, specifications, and maintenance for optimal performance.

1. Features at a Glance 2. Installation 3. First-Time Setup 4. Specifications 5. Controls and Functions 6. Connecting Components 7. Tuner Operation 8. Audio Adjustments 9. Care & Maintenance 10. Regulatory Information 11. Troubleshooting

Features at a Glance

Key components: Power amplifier, FM/AM tuner, preamplifier section, tuning meter, speaker terminals, input/output jacks.

Feature	Description
Power Output	38 watts per channel RMS into 8 ohms
Tuner Section	FM stereo and AM reception
Phono Input	For magnetic cartridge turntables
Tape Monitor	Dual tape monitor circuits
Loudness Control	Compensates for low volume listening
Tone Controls	Separate bass and treble adjustments
Speaker Selector	Switch for main and remote speakers
Headphone Jack	For private listening
Tuning Meter	Blue fluorescent signal strength indicator
Input Selector	Phono, Aux, Tuner, Tape 1, Tape 2

Installation

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

Connect speakers: Use speaker wire to connect to A and B speaker terminals.
Connect turntable: Use phono input for magnetic cartridge turntables.
Connect other sources: Use Aux input for CD players, tape decks, etc.
Connect antenna: FM 300-ohm terminals for best reception.
Plug into AC power outlet.

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

First-Time Setup

Power on receiver; allow warm-up time for optimal performance.

Set input selector to desired source (Phono, Tuner, Aux).
Adjust volume to minimum before powering on.
Tune FM stations: Use tuning knob and meter for best reception.
Set tone controls to flat position for initial listening.
Balance speaker output using balance control.

CAUTION! Always turn volume to minimum when switching sources or powering on.

Specifications

Power Output: 38 watts per channel RMS at 8 ohms
Total Harmonic Distortion: 0.3% or less at rated power
Frequency Response: 10Hz to 50kHz (+0, -3dB)
Input Sensitivity: Phono: 2.5mV, Aux: 150mV
Signal-to-Noise Ratio: Phono: 70dB, Aux: 85dB
Tuner Section: FM stereo, AM broadcast
Dimensions: 17-1/2" W x 5-1/2" H x 14-1/2" D
Weight: Approximately 24 lbs
Power Requirements: 120V AC, 60Hz

Controls and Functions

Front Panel: Power switch, input selector, volume, balance, bass, treble, loudness, speaker selector, tuning knob, function switches.

Main Controls: POWER, VOLUME, BALANCE, BASS, TREBLE, LOUDNESS, INPUT SELECTOR, SPEAKER SELECTOR, TUNING.

Tone Controls: Bass ±10dB at 50Hz, Treble ±10dB at 15kHz. Loudness: Compensates for Fletcher-Munson curves. Function Switches: Mono/stereo, high filter, tape monitor. Tuning: Flywheel-assisted tuning with meter.

Connecting Components

Rear Panel: Speaker terminals, phono input, aux input, tape monitor jacks, antenna terminals.

Turn off power before making connections.
Connect turntable to PHONO input (ground wire to ground terminal).
Connect CD player to AUX input.
Connect tape deck to TAPE MONITOR jacks.
Connect FM antenna to 300-ohm terminals.
Connect speakers observing correct polarity.

Tip: Use high-quality cables and keep signal cables away from power cords.

Tuner Operation

FM stereo and AM broadcast reception.

Set input selector to FM or AM.
Rotate tuning knob while watching signal meter.
For FM stereo, tune for maximum meter deflection and stereo indicator.
Use tuning knob for precise station selection.
For weak stations, switch to MONO for better reception.
Use high filter to reduce high-frequency noise if needed.

WARNING! Do not force tuning knob; gentle rotation provides best results.

Audio Adjustments

Tone controls and special functions for optimal sound.

Bass Control: Adjusts low frequencies. Treble Control: Adjusts high frequencies. Loudness: Engages bass boost at low volumes. Balance: Adjusts left/right channel balance. High Filter: Reduces high-frequency noise. Mono/Stereo: Selects mono reception for weak FM signals.

Care & Maintenance

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

CAUTION! Do not use solvents or abrasive cleaners. Keep away from moisture and extreme temperatures.

Regulatory Information

FCC compliant for home use. Manufactured to Marantz quality standards. This product complies with applicable safety standards. For service, contact authorized Marantz service centers. Original equipment from Superscope, Inc.

Troubleshooting

Symptom	Possible Cause	Corrective Action
No sound from speakers	Speaker connections/selector	Check speaker wires; verify speaker selector position.
Distorted sound	Overload/clipping	Reduce volume; check source level; verify speaker impedance.
Poor FM reception	Antenna/position	Improve antenna connection; reposition antenna.
Hum in phono	Ground connection	Ensure turntable ground wire connected to ground terminal.
Scratchy controls	Dirty contacts	Clean with contact cleaner; rotate controls fully several times.

Service: Contact authorized Marantz service center for internal repairs.

Note: This vintage equipment may require professional servicing for optimal performance.