Audio Research VT80SE Stereo Power Amplifier

The Audio Research VT80SE blends classic tube character with modern conveniences, delivering 75 watts per channel from a fully balanced design. By upgrading the original VT80’s KT120 tubes to the acclaimed KT150, it extends bandwidth and tightens bass, offering an even more lifelike presentation. Whether you stream digital files or spin vinyl, the VT80SE’s auto-bias feature and protective fuses make daily operation seamless, so you can immerse yourself in its refined valve sound. make this amp an ideal fit for those who want robust performance without overcomplicating their setup.

Key Features

• KT150 Output Tubes: Enhanced power handling, lifespan, and overall sonic refinement.
• Auto-Bias Circuit: Reduces manual upkeep by automatically adjusting bias for each output tube.
• Fully Balanced Design: Supports balanced XLR or single-ended RCA inputs, ensuring setup flexibility.
• Protective Fuses per Tube: Shields the amplifier from potential damage caused by tube failure.
• 75WPC Performance: Delivers full-bodied sound that easily drives a wide range of speakers.

Design and Build

Housed in Audio Research’s Foundation Series aesthetic, the VT80SE features an open chassis to showcase its quartet of KT150 tubes and pair of 6H30 driver valves. Sturdy steel construction underpins the amplifier, providing both mechanical stability and resonance control. Each component—from power transformers to circuit boards—is meticulously selected and hand-assembled in Minnesota, reflecting Audio Research’s five-decade legacy of careful craftsmanship.

Performance

Once powered, the VT80SE offers a warm, inviting midrange, complemented by well-defined bass and gently extended highs. Listeners can expect dynamic swings to feel natural rather than forced, while subtleties like ambient cues and harmonic overtones come through with greater clarity. The high-current KT150 valves play a notable role in presenting both subtle and grand musical passages, maintaining composure even when the volume spikes.

Technology

At the core of the VT80SE is a fully balanced topology that preserves signal integrity from input to output, supporting balanced or single-ended sources. The auto-bias circuit continuously monitors and adjusts the bias current for each KT150, making the occasional manual bias check a relic of the past. With protective fuses for each tube, the amplifier can withstand tube anomalies without jeopardizing the rest of your gear. Meanwhile, the 6H30 driver valves ensure a precise hand-off of the input signal to the KT150s.

Versatility and Compatibility

Rated at 75 watts per channel into 8 or 4 ohms, the VT80SE comfortably accommodates various speaker types—be they compact two-way monitors or large floorstanders. Separate taps for each impedance allow you to maximize efficiency in different systems, while balanced inputs help in constructing a fully balanced chain for minimal noise. With its moderate size and user-friendly features, the VT80SE slots into many modern living spaces and audio rigs.

The Listening Room Experience

At The Listening Room, we take pride in offering more than just high-fidelity audio equipment. We provide expert advice, personalized service, and a commitment to helping you find the perfect sound system for your space. From delivery to custom setup, our goal is to ensure that every piece of equipment you purchase performs at its absolute best in your environment. Trust us to be your partners in the pursuit of exceptional sound.

Specifications

• Power Output: 75 watts per channel continuous from 20Hz to 20kHz. 1kHz total harmonic distortion typically 1% at 75 watts, below 0.05% 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 very critical.)
• Power Bandwidth: (–3dB points) 7Hz to 60kHz
• Frequency Response: (–3dB points at 1 watt) 0.7Hz to 80kHz
• Input Sensitivity: 1.4V RMS BAL for rated output (25dB Bal gain into 8 ohms)
• Input Impedance: 300K ohms Balanced, 150K ohms Single-Ended
• Output Impedance: Non-inverting. Balanced input pin 2+ (IEC-268)
• Output Taps: 8 ohms, 4 ohms
• Output Regulation: Approximately 1.0dB 8Ω load to open circuit (Damping factor ~8)
• Overall Negative Feedback: 15dB
• Slew Rate: 10 volts/microsecond
• Rise Time: 4.0 microseconds
• Channel Separation: 112dB
• Hum & Noise: –84dBV weighted, 8 ohms tap
• Signal to Noise: 112dB
• Control: Power on/off, auto shut-off on/defeat, Input BAL/SE, RS232, 12V trigger
• Ambient Air Temperature: 30°C (86°F) maximum
• Power Supply Energy Storage: Approx. 350 joules
• Power Requirements: 100–125VAC 60Hz (200–250VAC 50Hz); 410 watts at rated output, 500 watts max, 230 watts idle, <1 watt in sleep mode
• Tubes Required: 2 matched pairs KT150 (power output), 2× 6H30 (driver)
• Dimensions: 19" (48.3cm) W × 10.33" (26.2cm) H × 18.45" (46.8cm) D to chassis, 19.40" (49.3cm) D to terminals
• Weight: 45.7lbs (20.7kg) net; 60.5lbs (27.4kg) shipping