VS55 Vacuum Tube Stereo Power Amplifier

VS55 Vacuum Tube Stereo Power Amplifier

We are happy to announce the introduction of a new vacuum-tube stereo power amplifier: the VS55, with a rated output of 50 watts per channel. The VS55 makes a wonderful companion to the recently introduced SP16 preamplifier. Together, these exciting new companion products enable you to assemble a true Audio Research music system at a more reasonable cost.

Like the SP16, the VS55 represents a fresh, new design direction for Audio Research. Using an open (rather than fully enclosed) chassis architecture, the VS 55 features a milled, anodized top plate through which the input and output tubes project upward. The chassis is finished in matte black with silver lettering, while the top plate is clear anodized with an inset logo. Behind the tubes and finished top plate are located the output and power transformers and a row of high-quality power-supply capacitors. The appearance is crisp and logical without being overly "retro."

The VS55 ships without a traditional cage-type top cover. An optional perforated cage which covers the tubes is available at additional cost.

Tube locations and types are screened next to each opening in the top plate, along with bias-adjustments for the two matched pair of 6550 EH output tubes. The chassis front has a power switch and LED indicator, while the rear provides gold binding posts labeled 0-4-8 ohms, L and R single-ended inputs, 12V in/out triggers for remote installation and L and R channel access points for a voltmeter (used when setting bias). The amp rests on four elastomer feet and uses a detachable 14-gauge power cord with I.E.C. socket. The virtue of the VS55 is found as much in its logical layout as in its sound: as shipped from the factory, all normal maintenance can be performed without removing a single panel or cover.

Best of all, you will find the sound of the VS55 a delightful complement to any Audio Research preamplifier, especially the SP16. While offering excellent soundstage focus and a vivid, liquid midrange, the VS55 also has surprising musical dynamics. Bass extension and impact are impressive compared to other amflifiers in this power range, thanks to generous power-supply energy reserves and to the efficient output-transformer design. In all, the VS55 bears the sonic hallmarks of being a true Audio Research amflifier: a quick, dynamic and powerful acoustic envelope surrounding an illuminated midrange of palpable lushness and realism. Matched with appropriate, high-quality loudspeakers and source components, the VS55 will give listening pleasure far beyond normal expectations in this price and power range. See your Audio Research retailer soon to schedule an audition of this exciting new power amplifier.

Control Functions: Power On/Off; External Bias Adjustment

Inputs: SE

Outputs: 0-4-8 ohm 5-Way Binding Posts

VS55 Specifications:

POWER OUTPUT: 50 watts per channel continuous from 20Hz to 20kHz. 1kHz total harmonic distortion typically 1% at 50 watts, below .05% at 1 watt. Approximate actual power available at "clipping" 52 watts (1kHz). (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) 12Hz to 50kHz.

FREQUENCY RESPONSE: (-3dB points at 1 watt) 1.0 Hz to 60 kHz.

INPUT SENSITIVITY: 1.1V RMS Single-ended for rated output. (25 dB gain into 8 ohms.)

INPUT IMPEDANCE: 100K ohms Single-ended.

OUTPUT TAPS: 8 ohms, 4 ohms.

OUTPUT REGULATION: Approximately 1.0 dB 8 ohm load to open circuit (Damping factor approximately 10).


SLEW RATE: 5 volts/microsecond.

RISE TIME: 5 microseconds.

HUM & NOISE: Less than 0.2mV RMS - 100dB below rated output (IHF weighted, input shorted).

POWER SUPPLY ENERGY STORAGE: Approximately 166 joules.

POWER REQUIREMENTS: 105-125VAC 60Hz (210-250VAC 50Hz) 320 watts at rated output, 500 watts maximum, 200 watts at "idle".

TUBES REQUIRED: (2 ) Matched pair 6550EH - Power Output; (3) 6N1P input and driver.

DIMENSIONS : 14" (35.6 cm) W x 7" (17.8 cm) H x 14" (35.6 cm) D. Rear connectors extend .88" beyond chassis.

WEIGHT: 32 lbs. (14.5 kg) Net; 38 lbs. (17.3 kg) Shipping.

Specifications subject to change without notice.

Audio Research Corporation
3900 Annapolis Lane North
Plymouth, Minnesota USA 55447-5447
Phone: 763-577-9700 Fax: 763-577-0323
©2003 Audio Research