MARANTZ 4400 FLAGSHIP QUADRAPHONIC RECEIVER – CUSTOM BLACK – WC-43 WOOD CASE – RESTORED – 1-YEAR WARRANTY

Professionally Restored by HQaudios – Fully Tested – Backed by Our 1-Year Warranty.

1. OVERVIEW

Up for sale is the Marantz 4400, the flagship of Marantz's quadraphonic receiver line from the mid-1970s and one of the most sought-after Marantz receivers of the era.

The defining feature of the 4400 is its built-in CRT oscilloscope, used for multipath tuning and real-time audio waveform display. Its four independent amplifier channels deliver 50 watts each in quadraphonic mode and can be bridged to 125 watts per channel in stereo. The 4400 also features the Gyro-Touch tuning wheel, Dolby noise reduction, Vari-Matrix synthesis, and a socket for optional matrix/CD-4 decoders.

This unit has been professionally restored, serviced, and tested by HQaudios. This particular unit features a custom black front-panel finish and comes with the Marantz WC-43 walnut wood case shown in the photos, included at no extra cost.

2. IMPORTANT FUNCTIONAL NOTE

The AM/FM tuner section is not functional because the tuning capacitor is damaged and no replacement part is currently available. The amplifier, phono stage, tape inputs, quadraphonic / Vari-Matrix circuitry, and oscilloscope have been serviced and tested. This receiver is therefore offered as a restored amplifier / phono / oscilloscope unit with a non-working tuner.

3. KEY HIGHLIGHTS

• Marantz 4400 flagship quadraphonic receiver
• Custom Black Front-Panel Finish
• Built-in CRT Oscilloscope
• 125 Watts x 2 in stereo mode / 50 Watts x 4 in quadraphonic mode
• Dolby Noise Reduction + Vari-Matrix
• AM/FM tuner not functional – damaged tuning capacitor
• Marantz WC-43 Walnut Wood Case Included
• Professionally restored and serviced by HQaudios
• 1-Year HQaudios Warranty

4. COSMETIC CONDITION

This unit is in Very Good restored vintage cosmetic condition, with visible but moderate age-related wear consistent with a 1970s component.

Please review all photos carefully, as they are an important part of the description.

Custom Black Front Panel: This unit features a custom black front-panel finish. The lettering and controls remain clearly readable.

Dial Glass / Front Glass: The front glass shows light surface scratches and scuffs visible under close inspection and certain lighting angles. These marks are cosmetic and should be considered part of the unit's vintage condition.

Oscilloscope CRT: The screen is clear and produces a bright, responsive trace.

Knobs / Controls / Sliders: The knobs, push-buttons, and balance sliders are intact and operate after service.

Top Heat-Sink / Vent Area: A few of the metal cooling fins / vent slots show minor bending. This area is largely covered from normal view when the included WC-43 wood case is installed.

Wood Case: The included Marantz WC-43 walnut wood case presents well overall with normal age-related wear and covers the top chassis / cooling area during normal use.

Rear Panel / Connections: Speaker terminals, RCA inputs, AM ferrite antenna, and rear-panel hardware are present and securely mounted.

5. HQAUDIOS RESTORATION & TESTING PROCESS

BEFORE RESTORATION

The Marantz 4400 was carefully inspected upon arrival to evaluate its mechanical, electrical, operational, and cosmetic condition. Particular attention was given to the power supply, high-voltage CRT oscilloscope circuit, four amplifier stages, phono board, Vari-Matrix circuitry, Dolby processing board, tuner section, controls, sliders, and dial illumination.

DURING RESTORATION

The power supply was repaired, and the high-voltage supply for the oscilloscope CRT was repaired to restore a stable trace.

Components replaced on this unit included:

• 2 × 470µF / 100V electrolytic capacitors

• 4 × 220µF / 50V electrolytic capacitors

• 20 × 47µF / 25V electrolytic capacitors

• 10 × 2SC1815 transistors

• 20 × 2SA1015 transistors

• 10 × 22kΩ 1/2W resistors

• 3 × 1N5408 rectifier diodes

The 8V dial and indicator lamps were replaced. The volume potentiometer, tone controls, sliders, and switches were cleaned and treated with contact cleaner. The chassis, faceplate, and wood case were cleaned and detailed.

The AM/FM tuner section was found to be non-functional due to a damaged tuning capacitor. As no replacement part is currently available, the tuner section remains non-working.

AFTER RESTORATION

Output power under load, channel balance, quadraphonic decoding, oscilloscope audio modes, tone controls, phono stage, tape inputs, and outputs were tested. The receiver then underwent an extended real-world listening test to evaluate overall stability and operation. The tuner section remains non-functional and is excluded from this functional claim.

6. SPECIFICATIONS

Brand: Marantz

Model: 4400

Type: Quadraphonic AM/FM Receiver with Built-in Oscilloscope

Era: Mid-1970s

Power Output – Stereo: 125 Watts per channel into 8 Ohms x2

Power Output – Quadraphonic: 50 Watts per channel into 8 Ohms x4

Frequency Response: 20Hz–20kHz

Total Harmonic Distortion: 0.15% at rated power

Damping Factor: 40

Inputs: Phono, Aux/CD-4, Tape 1, Tape 2

Built-In Tuner: NOT FUNCTIONAL on this unit

Special Features: Built-in CRT oscilloscope, Dolby noise reduction, Vari-Matrix, decoder socket

Power Requirement: 120V AC / 60Hz – Standard U.S. Operation

Dimensions: Approx. 19.3 W × 5.8 H × 15.3 D inches

Weight: Approx. 53 lbs

Finish: Custom Black Front Panel

Wood Case: Marantz WC-43 Walnut Wood Case Included

Condition: Restored / Serviced / Tested – Light Front-Glass Scratches; Minor Bent Cooling Fins

Warranty: 1-Year HQaudios Warranty

7. WHAT IS INCLUDED

• Marantz 4400 Quadraphonic Receiver
• Marantz WC-43 Walnut Wood Case

Only the items clearly shown in the photos or specifically listed in the description are included.

8. VIDEO TEST & SOUND DEMO

If you would like to see or hear the Marantz 4400 in operation, including the oscilloscope display, please message us through the platform. Additional operational photos or video demonstrations can be provided upon request.