Marantz 4430 Quadradial Receiver – Restored –Free Wood Case – 1-Year Warranty

MARANTZ 4430 QUADRADIAL 4 RECEIVER – 30W x4

Professionally Restored – Wood Case Included – 1-Year HQaudios Warranty

1. QUICK BUYER SUMMARY

Model: Marantz 4430
Type: AM/FM Quadraphonic Receiver
Power Output: 30 Watts per Channel x4 into 8 Ohms
Quad Capability: Discrete 4-Channel + Built-In Vari-Matrix
SQ Capability: SQ Decoder Position for Optional Compatible Plug-In Decoder Module
Tuner: Built-In AM/FM Analog Tuner
Wood Case: Walnut Wood Case Included – As Pictured
Power: 120V AC / 60Hz – Standard U.S. Operation
Service Status: Professionally Restored, Serviced, and Function-Tested
Cosmetic Condition: Very Good Vintage Condition
Warranty: 1-Year HQaudios Warranty

2. WHY THE MARANTZ 4430 STANDS OUT

The Marantz 4430 is one of the company's early four-channel Quadradial receivers, combining four independent 30-watt amplifier channels with AM/FM tuning, discrete four-channel inputs, Marantz's built-in Vari-Matrix circuit, separate front and rear tone controls, and the distinctive Gyro-Touch tuning system.

Its flexible architecture supports both conventional two-channel listening and period-correct four-channel systems.

3. AMPLIFIER, QUADRAPHONIC & TUNER ARCHITECTURE

• 30W/ch x4 into 8 Ohms – Four Independent Amplifier Channels
• Discrete 4-Channel + Built-In Vari-Matrix
• SQ Decoder Position for an optional compatible plug-in decoder module
• Gyro-Touch Tuning with classic Marantz blue dial illumination
• Separate Front / Rear Bass & Treble Controls
• Dimension Control for Vari-Matrix operation
• Front and Rear Headphone Outputs

4. HQAUDIOS RESTORATION & MULTI-POINT QUALITY CONTROL

Professionally Restored • Function-Tested • Final Listening Test Completed

BEFORE RESTORATION

As received, this Marantz 4430 was in the tired, neglected condition typical of a vintage receiver that had spent many years in storage and was no longer operating as it should.

Age-related oxidation affected controls, switches, push-buttons, and signal connections, while the dial illumination required service. The exterior also showed normal marks from decades of previous use.

On the bench, the power supply and power amplifier output stages were found faulty. A full inspection of the power supply, four amplifier stages, protection circuitry, phono section, Vari-Matrix circuitry, AM/FM tuner, controls, switches, meters, Gyro-Touch tuning system, and illumination was then carried out to determine the work required for this specific unit.

DURING RESTORATION

Based on the inspection results, this Marantz 4430 was restored according to HQaudios' technical standards while preserving its original engineering and vintage character.

The power supply and power amplifier output stages were repaired.

Documented component replacement on this unit included:

• 10 x 10µF / 50V electrolytic capacitors
• 10 trimmer potentiometers (VR)

Bias and DC offset were adjusted after repair to restore stable operation across all four amplifier channels.

Dial lamps and the FM Stereo indicator lamp were replaced to restore proper front-panel illumination and the classic Marantz blue glow.

The volume potentiometer, tone controls, push-buttons, and switches were thoroughly cleaned and treated with contact cleaner to remove oxidation and restore quiet, reliable operation.

The chassis, faceplate, controls, dial area, and included wood case were professionally cleaned and detailed while preserving the authentic vintage appearance of the Marantz 4430.

AFTER RESTORATION

Once restoration was completed, the Marantz 4430 underwent comprehensive functional and operational testing under real-use conditions.

Output operation, channel balance, quadraphonic functions, AM/FM tuner reception, phono stage, tone controls, inputs, outputs, speaker switching, meters, and illumination were checked for proper operation.

Bias, DC offset, left/right/front/rear channel operation, control response, tuner operation, and overall operating stability were verified.

Finally, the receiver underwent an extended real-world listening test to evaluate sound quality, channel consistency, quadraphonic operation, tuner performance, thermal stability, and long-term operating reliability before being approved and prepared for its next owner.

• Professionally Restored
• Components Replaced
• Illumination Restored
• Bias & DC Offset Adjusted
• Function-Tested
• Final Listening Test Completed

5. LISTENING CHARACTER

In a properly matched system, the Marantz 4430 provides a smooth and full-bodied vintage receiver presentation with useful tonal control and good channel separation.

In four-channel operation, its Discrete and Vari-Matrix modes allow a wider, more enveloping presentation, while conventional 2-channel mode supports standard stereo listening.

6. ACTUAL COSMETIC CONDITION

This receiver presents in very good vintage cosmetic condition, with normal signs of age and previous use consistent with a 1970s component.

The brushed aluminum faceplate, original knobs and controls, blue dial area, meters, and included walnut wood case present well overall. Minor age-related marks and wear may remain as shown.

Please inspect all product photos closely; they show the exact unit and form an important part of the condition description.

7. FACTORY SPECIFICATIONS

Type: AM/FM Quadraphonic Receiver
Era: Early 1970s
Power Output: 30 Watts per Channel x4 into 8 Ohms
Total Harmonic Distortion: Less than 0.3% at Rated Output
Damping Factor: Greater than 45 into 8 Ohms
Phono Input Sensitivity: 1.8mV
High-Level Input Sensitivity: 180mV
Operating Modes: Mono / 2-Channel / Discrete 4-Channel / Vari-Matrix / SQ Decoder Position
SQ Decoding: Optional Compatible Plug-In Decoder Module Required
Tone Controls: Separate Front / Rear Bass & Treble, Loudness, Hi Filter
Tuner: AM/FM
Speaker Load: 4–16 Ohms
Headphone Outputs: Front and Rear
Power Requirement: 120V AC / 60Hz – Standard U.S. Operation
Dimensions: Approx. 17.3 W × 5.4 H × 14.4 D inches
Weight: Approx. 38.5 lbs
Country of Manufacture: Japan
Wood Case: Walnut Wood Case Included – As Pictured
Warranty: 1-Year HQaudios Warranty

8. U.S. POWER COMPATIBILITY

This Marantz 4430 is configured for standard U.S. 120V AC / 60Hz operation and is ready for normal U.S. household power.

No step-down transformer is required for use in the United States.

International buyers should verify local mains voltage and use an appropriate voltage transformer when required.

9. SPEAKER & SYSTEM COMPATIBILITY

With four 30-watt amplifier channels, the Marantz 4430 is best paired with compatible passive speakers of suitable impedance and reasonable sensitivity.

For conventional stereo use, a standard front left/right speaker pair may be used.

For period-correct four-channel operation, four compatible speakers can be connected according to the Marantz operating instructions.

Avoid sustained clipping and confirm speaker impedance before operation.

10. WHAT IS INCLUDED

• One Marantz 4430 Quadradial 4 Receiver
• Walnut Wood Case – As Pictured

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

11. VIDEO TEST AND BUYER SERVICES

• Additional photos or an operational video demonstration may be available upon request
• Complimentary speaker and system-matching guidance is available before purchase
• A multi-item discount may be available when building a complete vintage system
• Selected high-value vintage audio equipment may be considered for trade-in

12. SHIPPING AND PACKAGING

Vintage quadraphonic receivers are heavy and delicate and require careful packing.

This Marantz 4430 will receive protective coverage around the faceplate, dial glass, Gyro-Touch tuning wheel, knobs, meters, wood case, corners, and rear connections, together with dense internal cushioning and a heavy-duty outer carton.

Tracking information will be provided after shipment, and signature confirmation may be required.

13. 1-YEAR HQAUDIOS WARRANTY

This receiver is covered by our 1-Year HQaudios Warranty for proper electronic and functional operation under normal home use.

Coverage does not include misuse, physical damage, unauthorized repair, incorrect wiring, incompatible equipment, amplifier clipping, incorrect voltage, or operation outside the manufacturer's intended specifications.

Please refer to the warranty terms supplied with the order for complete coverage details.

14. BUY WITH CONFIDENCE

Please review the complete description and all product photos before purchase.

Contact HQaudios if you need clarification regarding cosmetic condition, quadraphonic operation, SQ decoder compatibility, speaker matching, included items, shipping, or warranty coverage.

HQaudios – Vintage Audio Restored with Care.