D-80 Tube Power Amplifier By Audio Research

The D-80 tube amplifier delivers a rich, expansive tonal character with impressive resolution and musical authority, wrapped in a refined design inspired by premium reference-level tube amplification.

Consider the D-80 as a less expensive and streamlined version of the Reference S-80… the same amplifier, without the front-panel meter display, single-ended triode output mode, or RCA input jacks (balanced/XLR only).

Building on the legacy of the iconic “D” series amplifiers that helped define high-performance audio, the D-80 carries forward a tradition of exceptional sound quality, dynamic presence, and timeless engineering.

Drawing heavily from the acclaimed Reference 80S stereo tube amplifier platform, the D-80 features a fully balanced differential signal path with a pair of KT150 output tubes per channel. Carefully selected internal components contribute to excellent tonal depth, controlled bass response, and a spacious, immersive soundstage — all in a more accessible configuration.

The D-80 utilizes a full pentode design and is optimized for balanced audio systems, featuring balanced XLR inputs for seamless integration with high-end preamplifiers. Multiple 4-, 8-, and 16-ohm speaker taps provide flexible loudspeaker matching, while the fully balanced output stage drives both speaker terminals for enhanced performance.

An advanced auto-bias system continuously adjusts output tube bias in real time, compensating for tube aging and fluctuations in line voltage to help maintain consistent sonic performance over time.

Each unit is precision-built, thoroughly tested, and individually auditioned to ensure exceptional quality and listening performance.

Architeg
“The 80 watts per channel specification might sound technical, but what it translates to is an amplifier that can effortlessly drive a wide range of speakers, filling any room with immersive sound. You’re not just hearing music—you’re feeling it.”

https://www.architeg-prints.com/blog/audio-research-d-80-stereo-tube-amplifier-review-classic-power-meets-modern-muscle?srsltid=AfmBOor5l0hfm7qtlDs-3pycWLVwHT4UhAuv5LEPhYbOfbNuZi-mxMKV

Home Theater HiFi
“Find an Audio Research dealer and listen to this amplifier. Given its extremely high-quality construction, amazing sound, and consistently high resale value, you might just change your mind. Before you spend any fraction approaching 50% of the price of this amplifier, you owe it to yourself to at least hear the Audio Research VT80 tube amp. It’s that good.”

https://hometheaterhifi.com/reviews/amplifier/power-amplifier/audio-research-vt80-tube-power-amplifier-review/

• Power Output:
  • Power Output: 70 watts continuous from 20Hz to 20kHz. 1kHz total harmonic distortion typically 1% at 140 watts, below 0.04% at 1 watt. (Note that actual power output is dependent upon both line voltage and “condition” i.e.: if power line has high distortion, maximum power will be affected adversely, although from a listening standpoint this is not critical)
• Power Bandwidth: (-3dB points) 7Hz to 68kHz
• Frequency Response: (-3dB points at 1 watt) 0.7Hz to 94kHz
• Input Sensitivity: 1.4V RMS Balanced for rated output. (25.5 dB gain into 8 ohms). RMS SE for rated output.
• Input Impedance: 300K ohms Balanced (75K ohms SE)
• Output Polarity: Non-inverting. Balanced input pin 2+ (IEC-268)
• Output Taps: 4, 8, 16 ohms
• Output Regulation: Approximately 1.0dB 16 Ohm Load to Open Circuit (Damping factor approximately 8)
• Overall Negative Feedback: 15dB
• Slew Rate: 10 volts/microsecond
• Rise Time: 4.0 microseconds
• Power Requirements: 105-130VAC 60Hz (210-250VAC 50Hz) 420 watts at rated output. 221 watts at “idle”, 3.6 watts off Units for Japan: 100VAC 50/60Hz
• Tubes Required: 2 matched pair KT150 (Power output V1-V4); 2 6H30 (Gain stage V5, V6)
• Dimensions:
  • Width 18.5” (47 cm) chassis; 19.0” (48.26 cm) faceplate
  • Height 10.5” (26 cm)
  • Depth 18.5” (47 cm)
  • With handles & connectors: 21” (53.3 cm)
• Weight:
  • 62 lbs. (28.2 kg) Net
  • 73 lbs. (32.7 kg) Shipping