Audio Research VT100 MKII Vintage 100W Tube Amplifier - 110V/220V

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Please see our VT100 video review below for design and construction details.

This particular piece is finished in classic ARC silver, and is the later MKII version featuring active cooling and larger power supply.

All VT100's can be converted to native 220V if you have the knowledge. Please let us know when ordering if you'd like it reconfigured.

Good condition with some scratches and signs of use. Serviced, biased, and ready to go!

Service Notes:

Stressed screen, plate load, and bias reference resistors replaced. Optimal tubes selected for driver and power output sections. Front end adjustment and bias set to service manual specifications.

Our Testing Process for Amplifiers (Tube) at SkyFi:

We start with a visual inspection of all internal components to make sure there are no signs of stress or aging. Capacitors are checked for telltale sings of bulging or leaking, resistors are checked for signs of overheating or cracking, and tubes are inspected for signs of stress overheating or cracking.

We then power up the unit carefully and run a simple 1k sine wave while monitoring the output on an oscilloscope for signs of distortion or noise. Finally we run the amplifier to its full rated power into the appropriate resistive load provided by our Sencore amplifier tester. If there is an issue, it will usually be noticeable at this point. If it all looks clean we will often test for THD (Total Harmonic Distortion) measured by our Keithley distortion meter, and compare it against the original manufacturers specifications. The amplifier the remains powered on to "burn in" on our test bench for a few hours to make sure there are no heat related issues. If there are balanced inputs available they will also be tested.

We also test all tubes for output gain and leakage on our calibrated B&K 747 tester against the original manufacturers specifications. If needed, the tubes will be replaced from our vast NOS (New Old Stock) vintage or modern inventory.

Final testing involves pushing actual music thorough the amplifier. We've learned over time that some issues are only noticeable to a trained ear while listening to familiar source material. Our test bench has reference vintage KEF speakers that we're very familiar with which quickly reveal any discrepancies. Some amplifiers will then move into our listening room where they are tested with our in-house reference speakers of choice.

Specifications:

Stereo tubed power amplifier with balanced inputs and 4, 8, and 16 ohm output transformer taps.

Tube complement: 4 matched pairs of 6550C output tubes, 4 6H30 driver tubes.

Maximum output power: 110Wpc continuous, 20Hz–20kHz at 1kHz with THD typically 0.3% at 110W, 0.03% at 1W; 120W at clipping (20.8dBW).

Frequency response: 0.6Hz–90kHz, –3dB.

Input sensitivity: 1.8V RMS balanced for rated output (24dB balanced gain into 8 ohms).

Input impedance: 300k ohms balanced.
Output polarity: non-inverting.
Damping factor: approximately 12.
Hum & noise: 0.2mV RMS, 106dB below rated output (IHF weighted, input shorted).

Power requirements: 105–125VAC, 60Hz (210–250VAC, 50Hz), 630W at rated output, 800W maximum, 410W at "idle."

Dimensions: 19" (483mm) W by 8.75" (222mm) H by 19.5" (495mm) D. Handles extend 1.5" (38mm) forward.

Weight: 67.4 lbs (30.7kg) net, 83 lbs (37.8kg) shipping.

Please click here for detailed specifics regarding our specialized packing process that separates us from the rest.