Audio Research D300 Stereo Amplifier

The Audio Research D300 is a legendary high-power solid-state amplifier from one of America’s most respected high-end audio manufacturers. Designed to deliver exceptional control, transparency, and musical authority, the D300 represents Audio Research’s philosophy of combining precision engineering with a natural, uncolored sound signature.

Built with a robust dual-mono topology, massive power reserves, and audiophile-grade components, the D300 is capable of driving demanding loudspeakers with ease while maintaining refinement, speed, and dynamic accuracy. This unit has been professionally serviced and tested, ensuring reliable operation and long-term performance for serious audiophiles and collectors.

Condition: Excellent – Serviced, tested, and cleaned

Model: Audio Research D300

Type: Stereo Power Amplifier

Protection Plan: 1-Year Warranty Included

Free Support: Must be used before requesting return

SKU: 151SELC0001

Customer Service:

Once your item arrives, if you have questions about how your item functions or proper settings, please CONTACT US.

TRADE-IN PROGRAM

“If you have any vintage audios (receivers, speakers, cassette, reel to reel…) & want to upgrade with the serviced one, don’t hesitate to contact us for the best deal. You only need to pay for the difference between yours & mine….”

Note:

The actual color of the product may sometimes differ slightly from the photos due to lighting conditions, temperature, and the device used. Some angles in the photos may not fully reflect the product’s condition. Please read the description carefully and feel free to message us if you have any questions.

SPECS:

Power output: 160 watts per channel into 8Ω (stereo)

Frequency response: 1Hz to 150kHz

Damping factor: 130

Gain: 25.7 dB

Input sensitivity: 1.9V

Signal to noise ratio: 116dB

Speaker load impedance: 4Ω (minimum)

Dimensions: 18.90 x 7.01 x 12.87 inches

Weight: 48.06 lbs

Year: 1993

KEY FEATURES

• High-Current Solid-State Design – Exceptional speaker control and dynamic authority
• Massive Power Output – Designed to drive low-impedance and power-hungry loudspeakers with ease
• Dual-Mono Architecture – Independent left/right channels for superior channel separation
• Wide Bandwidth & Low Distortion – Clean, transparent sound with excellent resolution
• Professional-Grade Power Supply – Large transformer and high-capacity filter banks
• Minimalist Industrial Design – Signature Audio Research black chassis with heavy heatsinks
• Built for Longevity – Rugged construction intended for decades of reliable use

REFURBISHED

This Audio Research D300 has undergone a professional refurbishment process to restore its electrical integrity, thermal stability, and sonic accuracy. All critical systems were inspected, serviced, and verified to ensure the amplifier performs at its intended high-end reference level.

Complete Electronic Service

• Power supply capacitors inspected and replaced where necessary with high-quality audio-grade components
• Voltage rails stabilized to ensure consistent output under load
• Aged components showing drift or stress replaced to maintain circuit reliability

Semiconductor & Signal Path Care

• Output devices and driver stages tested for matching and stability
• Signal path components inspected to ensure low noise and accurate signal transfer
• Internal wiring and connections checked and secured

Relay, Protection & Control Systems

• Protection circuits tested for correct operation
• Input/output relays cleaned and verified for reliable channel engagement
• Soft-start and safety systems confirmed to function within factory tolerance
• Replace the 8V radio backlight, transistor preamp part

Thermal & Mechanical Service

• Heatsinks cleaned to optimize heat dissipation
• Internal chassis thoroughly cleaned and detailed
• Mechanical fasteners tightened and inspected

Calibration & Bench Testing

• Bias and operating parameters adjusted to Audio Research specifications
• Bench-tested using precision measurement equipment
• Extended run-in testing performed to verify thermal stability and channel balance

Cosmetic Detailing

• Exterior chassis carefully cleaned and preserved
• Front panel and controls detailed to maintain the original Audio Research aesthetic

Result:
A fully serviced Audio Research D300 that delivers powerful, controlled, and transparent sound, with excellent speaker grip and long-term operational stability—ready to anchor a serious high-end audio system.

SUGGESTED PAIRINGS

• Preamplifiers: Marantz 3600, Pioneer SPEC-1, Sansui CA-2000
• Amplifiers / Receivers: Marantz 2275 / 2330B, Pioneer SX-1250 / SX-5590, Sansui G-7000
• Tape Reels: Maxell UD / XL-I, TDK Audua, BASF / EMTEC
• Speakers: JBL L100, Klipsch Cornwall, Tannoy Monitor series

🎁 GET A $100 VOUCHER INSTANTLY WHEN YOU BUY A COMBO!

PACKAGING & SHIPPING

Secure Packaging:

• Each unit is carefully packed using:

• Nylon wrap and sealed inner carton

• Custom EPE foam corners to protect edges

• Double-wall outer box for shock resistance

• Plastic straps + handling labels to ensure safe transit

Shipping Details:

• Dispatch Time: Ships within 3 business days

• Carrier: UPS Ground (tracked & insured)

• Signature Required: Yes (as buyer’s request)

• Transit Time: Typically 3–7 business days (USA)

International Shipping:

We offer global delivery through the eBay International Shipping Program. eBay handles customs, duties, and tracking.

📦 Note: Packaging may vary slightly depending on unit size or model, but safety and protection are always our top priority.