Marantz 4140 Quadraphonic Amplifier – 70W Stereo / 25W x4 – Professionally Restored – Wood Case Included – 1-Year Warranty

$2,999

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  • Authentic Marantz 4140 Quadraphonic Console Amplifier
  • Bridged Power Output: 70 Watts x2 (Stereo) or 25 Watts x4 (Quadraphonic)
  • Four independent Illuminated VU Power Meters
  • Exclusive Vari-Matrix Circuit and SQ-Decoder capabilities
  • Independent Front and Rear Tone Controls (Bass, Midrange, Treble)
  • Professionally Restored and Serviced by HQaudios
  • Amplifier stages, power supply, and matrix functions inspected and tested
  • Real-world operational and listening test performed
  • Carefully packed for safe delivery
  • Backed by Our 1-Year HQaudios Warranty
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SKU: 151TRSH0179 Categories: ,
SOUND DEMO / AUDIO EXPERIENCE

Sound Demo

For the best audio experience, please use headphones or external speakers.

Marantz 4140 Stereo 2 / 4-Channel Integrated Amplifier – Wood Case Included
Professionally Restored by HQaudios – Inspected & Tested – Backed by Our 1-Year Warranty

KEY HIGHLIGHTS
Marantz 4140 stereo 2 / quadraphonic 4-channel integrated amplifier
70 W x 2 in stereo mode or 25 W x 4 in 4-channel mode
Four illuminated VU power meters
Vari-Matrix quadraphonic circuit with provision for an optional SQ decoder module
Independent front and rear bass / mid / treble controls
Wood case shown in the photos included
Professionally restored and tested by HQaudios
Backed by our 1-Year HQaudios Warranty

PRODUCT OVERVIEW
The Marantz 4140 is a mid-1970s stereo 2 / 4-channel integrated amplifier, produced from 1975 to 1978, built to run either as a high-power stereo amplifier or as the heart of a quadraphonic system.
It delivers 70 W x 2 in stereo operation or 25 W x 4 in 4-channel operation, with four illuminated VU power meters, Marantz Vari-Matrix circuitry and independent front and rear bass, midrange and treble controls.
We restored this unit with careful attention to technical operation and cosmetic presentation, while preserving the original Marantz design and character.


HQAUDIOS RESTORATION & TESTING

Before Restoration
When we received this Marantz 4140, we performed a complete visual, electrical, and functional inspection before beginning the restoration process.
The inspection covered the power supply, amplifier stages, phono and preamplifier sections, controls, switches, meters and lamp illumination, and was used to determine the service needed for this specific unit.

During Restoration
We restored this Marantz 4140 according to our HQaudios restoration standards while preserving the original Marantz design and components.
Amplifier & Power Supply: We inspected and serviced the amplifier circuitry and power supply, addressing the components identified during the technical inspection.
Controls & Switches: The volume control, tone controls, sliders and push-button switches were cleaned.
Meter Illumination: The VU meter illumination was serviced.
Cleaning & Detailing: The chassis, faceplate, controls and wood case were cleaned and detailed.

After Restoration / Final Testing
After the restoration was completed, the unit underwent final functional and listening tests.
Amplifier Output: All channels were checked for proper, consistent output in stereo and 4-channel modes.
Quadraphonic Functions: Vari-Matrix and 4-channel operation were checked.
Tone & Balance Controls: Front and rear bass, mid, treble and balance controls were checked for smooth, noise-free adjustment.
Inputs & Meters: Phono, tuner, aux and tape inputs and the VU meters were checked.
Listening Test: The amplifier was evaluated using real music playback over an extended session.
Final QC: A complete visual and functional quality-control inspection was completed before release.

CONDITION

Technical Condition
Amplifier & Power Supply: Serviced
Controls & Switches: Cleaned and operating
VU Meters: Illumination serviced, meters responding
Operating Modes: Stereo and 4-channel modes checked
Power: AC 120V

Cosmetic Condition
Faceplate: Brushed aluminum faceplate with legible original markings
Knobs & Sliders: Original controls present
VU Meters: Four illuminated meters present
Wood Case: Included, as shown in the photos
Rear Panel: Original speaker terminals, RCA connections and rear-panel controls
Overall Presentation: A vintage amplifier with normal signs of age and previous use. Please review all photos for exact cosmetic details.

Amplifier Serviced
All Channels Tested
Final Listening Test Completed

SPECIFICATIONS
Brand: Marantz
Model: 4140
Type: Stereo 2 / 4-Channel Integrated Amplifier
Years: 1975 – 1978
Power Output: 70 W x 2 (stereo) / 25 W x 4 (4-channel), 8 ohms, 20 Hz – 20 kHz
Total Harmonic Distortion: 0.3%
Intermodulation Distortion: 0.3%
Frequency Response: 20 Hz – 20 kHz, ±1.0 dB (at 1 W)
High-Level Input: 150 mV / 100k ohms
Damping Factor: 40
Quadraphonic System: Vari-Matrix; provision for optional SQ decoder module
Power: AC 120V

WHAT IS INCLUDED
1 Marantz 4140 Integrated Amplifier
Wood case shown in the listing photos
Attached AC power cord
Only the items specifically listed above are included. Speakers, cables, remote control and other accessories are not included.

SHIPPING & PACKAGING
Your vintage audio equipment will be professionally packed by HQaudios using protective materials appropriate for its size, weight, and construction. Large or heavy items may be palletized and shipped by freight when required for safer transportation.
HQaudios Professional Shipping and Packaging
Please contact us before purchase for the most current availability information.

1-YEAR WARRANTY & CUSTOMER SUPPORT
Your purchase is backed by our 1-Year HQaudios Warranty. Our team provides support before and after your purchase. If you have questions about setup, operation, compatibility, or your order, please contact HQaudios for assistance.

MORE FROM HQAUDIOS

HQaudios Vintage Audio Repair and Restoration
HQaudios Custom Audio Projects

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