audio research

Tube stereo power amplifier.

From the ARC website

The VT200 vacuum tube stereo power amplifier is the most powerful of the three VT-series models. Rated at 200 watts per channel into a wide range of speaker loads, the VT200 encompasses a "dual mono" circuit layout reaching back to the massive single power transformer. Eight matched pair of 6650C output tubes and 674 joules of distributed energy storage give the VT200 unwavering control over the most difficult speaker loads, without sacrificing dynamic freedom or musical nuance.
Separate left and right input and output circuit boards, with distributed power supplies, keep signal path lengths at a minimum for quicker transient attack and explosive musical dynamics. As with other VT models, constant-current sources in the input stage help maintain stable drive characteristics and differential balance of the output stage under the rapidly changing demands of actual music reproduction. Ultralinear output transformers with partial cathode coupling to the output terminals give the VT200 higher efficiency and lower output impedance than conventional vacuum-tube amplifiers. This results in better control of the loudspeaker throughout its frequency and impedance spectrum.

Both single-ended (100K ohms) and balanced (200K ohms) inputs are included to allow use with any high-quality stereo preamplifier. Custom-machined, gold-over-brass five-way output terminals allow a secure, high-contact connection to a variety of speaker impedances: 1, 2, 4, 8 or 16 ohms.

Internally, the VT200 presents a very open architecture within a spacious, rugged chassis. A single cooling fan operable at three different speeds provides unobstrusive cooling of interior components, including the vacuum tubes mounted along the chassis sidewalls.

Biasing of the output tubes is easily accomplished via two trim pots for each channel, accessible through holes located along each sidewall of the chassis. Complete retubing kits of tested, selected and matched tubes for the VT200 are available through authorized Audio Research dealers, or from the factory.



VT200 MKII (2001)

The VT200MKII has totally new audio circuit boards incorporating a JFET input, 6H30 twin triode cathode followers and 6H30 drivers. Output tubes continue to be the reliable and proven 6550C, 08 per channel. New high performance Teflon capacitors have also been added in several locations. Operational features remain unchanged except for the important addition of a 12 V trigger for remote system power on / off and a small rear panel toggle switch to select single ended / balanced inputs (no shorting links needed).

Platinum grey faceplate.

MSRP (US new retail)
$8,995. Later increased to $9,995. (VT200)
$9,995. Increased to $10,995 on Feb 5 2001. (VT200 MKII)


Power output 200 watts per channel continuous from 20Hz to 20kHz. Approximate actual power available at "clipping" 210 watts (1kHz)
Power bandwidth (-3dB points) 12Hz to 120kHz
Frequency response (-3dB points at 1 watt) .5Hz to 200 kHz
Input sensitivity 2.5V RMS (Bal or SE) for rated output. (27 dB gain into 16 ohms)
Input impedance 200K ohms Balanced, 100K ohms Single-ended
Output taps 1, 2, 4, 8, 16 ohms
Output regulation Approximately 0.8dB 16 ohm load to open circuit
Overall negative feedback 10 dB
Damping factor 11
Distortion 1kHz total harmonic distortion typically 1% at 200 watts, below .01% at 1 watt.
Slew rate 25 volts/microsecond
Rise time 1.5 microseconds
Hum & noise Less than 0.2mV RMS < 109dB below rated output (IHF weighted, input shorted, 16 ohm output)
Power supply energy storage 674 joules
Power requirements 105-125VAC 60Hz (210-250VAC 50Hz) 990 watts at rated output, 1200 watts maximum, 680 watts at "idle"
Tube complement VT200: (8 matched pairs) 6550C power output, (6) 6922 driver, (4) 6922 input
  VT200 MKII: (8 matched pairs) 6550C power output, (6) 6H30 driver
Dimensions 19" (48.3 cm) W x 10.5" (26.7 cm) H x 23.6" (60.0 cm) D. Handles extend 1.5" (3.8 cm) forward
Weight 118 lbs. (46.5 kg) Net; 148 lbs. (58.3 kg) Shipping.


Vol. 21 No. 11