Marantz 105B Manual

The Marantz 105B is a professional stereo preamplifier known for its high-quality audio performance, versatile input/output options, and robust construction. Featuring multiple phono and line-level inputs, tone controls, tape monitoring, and exceptional signal-to-noise ratio, this unit is designed for audiophiles and professional audio applications. Below are key sections covering features, installation, operation, specifications, and maintenance.

Features at a Glance

Key components: High-quality preamplifier circuitry, multiple input selection, tone controls, tape monitoring, and precision volume control.

Feature	Description
Phono Inputs	MM and MC cartridge compatibility with adjustable loading
Line Inputs	Multiple auxiliary inputs for CD, tuner, tape
Tone Controls	Bass and treble adjustment with bypass option
Tape Monitoring	Dual tape loops for recording and playback
Headphone Output	Front panel 1/4" jack for private listening
Power Supply	Dedicated linear power supply for clean operation
Volume Control	Precision stepped attenuator for accurate level setting
Input Selector	Rotary switch for source selection
Muting	Instant mute function for interruptions
Balance Control	Left/right channel balance adjustment

Installation

Unpack and inspect contents. Place on stable, level surface away from heat sources.

1. Connect audio sources: Use appropriate cables for phono, CD player, tuner, etc.
2. Connect to power amplifier: Use high-quality interconnects from main outputs.
3. Connect tape decks: Use tape 1 and tape 2 loops for recording equipment.
4. Plug into AC power outlet.

WARNING! Ensure proper ventilation; do not block ventilation openings. Use correct phono grounding.

First-Time Setup

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

1. Input selection: Rotate INPUT selector to desired source (Phono, CD, Tuner, etc.).
2. Volume setting: Start with volume at minimum, gradually increase to desired level.
3. Tone controls: Set to flat position initially, adjust to preference.
4. Phono setup: Match cartridge type (MM/MC) and adjust loading if applicable.

CAUTION! Always turn volume down before switching sources or powering on/off.

Specifications

• Frequency Response: 10Hz - 100kHz (+0/-3dB)
• Total Harmonic Distortion: <0.005% at 1kHz
• Signal-to-Noise Ratio: >90dB (line inputs)
• Input Sensitivity: Phono: 2.5mV, Line: 150mV
• Input Impedance: Phono: 47kΩ, Line: 50kΩ
• Output Level: 1V RMS at rated input
• Tone Control Range: ±10dB at 100Hz and 10kHz
• Power Requirements: 120V AC, 60Hz, 15W
• Dimensions: 17" W × 4" H × 12" D
• Weight: 12 lbs

Controls and Settings

Front Panel: Power switch, Input selector, Volume control, Balance, Tone controls, Mute, Tape monitor switches.

Rear Panel: Phono inputs, Line inputs, Tape loops, Main outputs, AC power cord.

Input Selection: Phono, CD, Tuner, Aux 1, Aux 2, Tape 1, Tape 2. Tone Controls: Bass ±10dB at 100Hz, Treble ±10dB at 10kHz. Tape Monitoring: Source/Tape selection for each tape loop. Balance: Continuous adjustment from full left to full right.

Connecting Components

Phono: Connect turntable to phono inputs, ensure ground wire connected. Line Level: CD player, tuner to respective inputs. Tape Decks: Connect record outputs to tape inputs, play outputs to tape outputs.

1. Turn off all components before making connections.
2. Use high-quality shielded cables for all connections.
3. Ensure proper grounding of turntable.
4. Keep signal cables away from power cords.

Tip: Use balanced connections where possible for best noise rejection.

Operation Guide

Daily operation procedures for optimal performance.

1. Power sequence: Turn on preamplifier first, then power amplifier.
2. Source selection: Rotate input selector to desired source.
3. Volume adjustment: Use smooth, gradual movements of volume control.
4. Tape recording: Select source, engage tape monitor for recording verification.
5. Headphone use: Plug headphones into front panel jack, automatically mutes main outputs.
6. Muting: Press mute button for instant silence without changing volume setting.

WARNING! Never operate with cover removed. Avoid excessive volume levels.

Maintenance

Regular maintenance ensures long-term reliability and performance.

1. Cleaning: Use soft, dry cloth for exterior. Avoid chemical cleaners.
2. Contact cleaning: Use contact cleaner on controls if scratchiness develops.
3. Ventilation: Keep vents clear of dust and obstructions.
4. Storage: Cover unit when not in use for extended periods.

CAUTION! Unplug unit before any cleaning. Do not use compressed air inside unit.

Technical Specifications

• Phono Overload: 200mV at 1kHz
• RIAA Accuracy: ±0.5dB 20Hz-20kHz
• Channel Separation: >70dB at 1kHz
• Maximum Output: 10V RMS
• Output Impedance: 100Ω
• Headphone Output: Suitable for 32-600Ω headphones
• Power Consumption: 15 watts maximum
• Operating Temperature: 41°F to 95°F (5°C to 35°C)
• Hum and Noise: Phono: -80dB, Line: -90dB

Warranty Information

Marantz 105B comes with 2-year limited warranty covering defects in materials and workmanship. Warranty registration required within 30 days of purchase. Service available through authorized Marantz service centers. Keep original receipt for warranty claims.

Troubleshooting

Symptom	Possible Cause	Corrective Action
No sound	Power/connections/mute	Check power; verify connections; disengage mute
Hum or noise	Grounding/cables	Check phono ground; replace cables; separate from power cords
Intermittent operation	Dirty controls	Clean controls with contact cleaner; check connections
Distorted sound	Overload/connections	Reduce input level; check source component; verify proper connections
Channel imbalance	Balance control/source	Adjust balance control; check source component; swap cables

Service: Contact authorized Marantz service center for internal repairs.

Support: Marantz Customer Service: 1-800-XXX-XXXX; www.marantz.com