Marantz 2270 Receiver Manual

The Marantz 2270 is a classic stereo receiver from the 1970s featuring 70 watts per channel RMS power, high-quality phono inputs for turntables, AM/FM tuner with excellent reception capabilities, multiple audio inputs, tone controls, loudness compensation, and distinctive blue-lit tuning dial. Below are key sections for features, installation, operation, specifications, and maintenance.

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: Power amplifier section, preamplifier with phono stage, AM/FM tuner, input/output terminals, front panel controls.

Feature	Description
Power Output	70 watts per channel RMS into 8 ohms
Phono Inputs	MM cartridge compatible with adjustable capacitance
Tuner Section	AM/FM stereo with muting and signal strength meter
Tone Controls	Bass and treble with turnover frequency selection
Loudness Control	Compensates for Fletcher-Munson curves at low volumes
Input Selection	Phono, Aux, Tape 1, Tape 2
Speaker Outputs	Main and Remote speaker terminals
Headphone Jack	Front panel 1/4" stereo headphone output
Power Switch	Main power with illuminated indicator
Tuning Dial	Blue-lit analog tuning meter with signal strength

Installation

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

Connect speakers: Use speaker wire to connect to Main speaker terminals (A or B).
Connect turntable: Use phono input for magnetic cartridge turntables.
Connect other sources: Use Aux input for CD players, tape decks, etc.
Connect antenna: FM antenna to 300 ohm terminals; AM loop antenna.
Plug into AC power outlet.

WARNING! Ensure proper ventilation; do not block ventilation slots. Use correct speaker impedance (4-16 ohms).

First-Time Setup

Power on receiver; allow 30 seconds for warm-up.

Select input source: Turn selector knob to desired input (Phono, Aux, etc.).
Adjust volume: Start with volume at minimum, then gradually increase.
Tune FM stations: Use tuning knob and signal strength meter for best reception.
Set tone controls: Begin with flat settings (bass and treble at 12 o'clock).
Adjust loudness: Engage for low-volume listening if desired.

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

Specifications

Power Output: 70 watts per channel RMS at 8 ohms.
Frequency Response: 10Hz to 50kHz (+0, -1dB).
Total Harmonic Distortion: Less than 0.1% at rated power.
Input Sensitivity: Phono: 2.5mV; Aux: 250mV.
Signal-to-Noise Ratio: Phono: 75dB; Aux: 90dB.
Tuner Section: FM sensitivity: 1.8uV; AM sensitivity: 50uV.
Tone Controls: Bass: ±10dB at 50Hz; Treble: ±10dB at 15kHz.
Power Requirements: 120V AC, 60Hz, 350 watts max.
Dimensions: 17-1/2" W × 5-3/4" H × 15" D.
Weight: 38 lbs.

Controls and Settings

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

Main Controls: Input Selector (Phono, Aux, Tape 1, Tape 2), Volume, Balance, Bass, Treble, Loudness, Speaker Selector (A, B, A+B, Off), Tuning, Function Switches (Mono/Stereo, High Filter, Muting).

Tone Controls: Bass (±10dB at 50Hz), Treble (±10dB at 15kHz). Filter: High filter reduces high-frequency noise. Muting: Reduces background noise between stations. Mono: Combines stereo signals for weak reception.

Connecting Components

Speaker Connections: Main and Remote speaker terminals. Source Connections: Phono, Aux, Tape inputs/outputs.

Turn off power before making connections.
Connect speakers: Ensure polarity correct (red to red, black to black).
Connect turntable: Use phono input only for turntables with magnetic cartridges.
Connect other sources: CD players, tape decks to Aux or Tape inputs.
Connect antennas: FM dipole antenna to 300 ohm terminals; AM loop antenna.

Tip: Use high-quality interconnects and speaker wire for best performance.

Tuner Operation

AM/FM stereo tuner with signal strength meter and tuning meter.

Select FM or AM: Turn function selector to desired band.
Tune stations: Rotate tuning knob until tuning meter centers.
Stereo reception: Stereo indicator lights when receiving stereo broadcast.
Muting: Engages to reduce noise between stations.
Mono switch: Use for weak FM signals to reduce noise.
High filter: Reduces high-frequency noise on AM and weak FM.
Preset stations: Use tape monitor switches as memory presets (unofficial).

WARNING! Do not force tuning knob; turn gently for precise tuning.

Audio Adjustments

Tone controls, loudness compensation, and filter options.

Bass Control: Adjusts low frequencies. Treble Control: Adjusts high frequencies. Loudness: Compensates for natural hearing deficiencies at low volumes. Balance: Adjusts left/right channel balance. High Filter: Reduces high-frequency noise and hiss.

Care & Maintenance

Unplug before cleaning. Use soft, dry cloth for exterior; compressed air for dust removal from vents.

CAUTION! Do not use liquid cleaners; avoid moisture near electrical components. Have unit serviced by qualified technician only.

Regulatory Information

FCC compliant for home audio equipment. Manufactured to meet industry standards for audio performance and safety. Copyright © 1970s Marantz Company. For historical reference and support, consult vintage audio specialists or authorized service centers.

Troubleshooting

Symptom	Possible Cause	Corrective Action
No sound from speakers	Speaker selector/connections	Check speaker selector setting; verify speaker connections; check fuse.
Distorted sound	Overload/incorrect input	Reduce volume; ensure turntable connected to phono input only.
Poor FM reception	Antenna/placement	Reposition FM antenna; check connections; extend dipole fully.
Hum or noise	Grounding/cables	Check ground connections; use shielded cables; separate from power cords.
Lights not working	Bulbs/power	Replace indicator bulbs; check power connection.
Overheating	Ventilation/impedance	Ensure adequate ventilation; check speaker impedance compatibility.

Service: Consult qualified vintage audio technician for repairs. Original schematics available from Marantz archives.