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).
OVERALL NEGATIVE FEEDBACK
12.5dB.
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.
Vacuum Tube Amplifier SE-1 (single ended output)
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 VS55 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 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 amplifiers 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 amplifier: 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.
