audio research

Integrated tube stereo amplifier.

From the ARC website

The CA50 is the first integrated power amplifier ever offered by Audio Research. It includes a 50-watt per channel all-vacuum-tube, push-pull Class AB power amplifier using 6922 twin triode tubes for input and driver stages, and 6550 power output tubes (one matched pair per channel). Constant-current source technology, distributed power supplies, and a dual-mono internal layout back to the main power transformer all contribute to the sonic power and finesse this model is capable of delivering. The volume control and input switching of the CA50 are via microprocessor- controlled relays, and a complete-function handheld IR remote control is standard.

The ample chassis dimensions and functional internal layout of the CA50 eliminate the need for fan cooling, yet offer the covenience and easy installation of a single-chassis integrated unit. Up to 6 input sources including tape are accommodated. Output terminals are custom-machined, heavy-duty, gold-over-brass 5-way posts. In addition, a full-range, single-ended set of "Sub bass" outputs allow easy connection to a powered subwoofer or even to another power amplifier, perhaps for a remote system.




Platinum grey faceplate.

MSRP (US new retail)
$3,495. Later increased to $3,995.


Power output 45 watts per channel continuous from 20Hz to 15kHz. Approximate actual power available at "clipping" 50 watts (1kHz)
Power bandwidth (-3dB points at 1 watt) 18Hz to 40kHz
Frequency response (-3dB points at 1 watt) 2Hz to 50kHz
Input sensitivity 0.3V RMS for rated output. (35dB gain into 8 ohms (optional 38dB))
Input impedance 100K ohms Single-ended
Output taps 8 ohms, 4 ohms
Output regulation Approximately 1.0dB 8 ohm load to open circuit
Overall negative feedback 7 dB
Damping factor 13
Distortion 1kHz total harmonic distortion typically 2% at 45 watts, below .05% at 0.1 watt
Slew rate 10 volts/microsecond
Rise time 5 microseconds
Hum & noise Less than 1.0mV RMS 85dB below rated output (IHF weighted, input shorted)
Power supply energy storage 183 joules
Power requirements 105-125VAC 60Hz (210-250VAC 50Hz) 290 watts at rated output, 330 watts clipping, 190 watts at "idle"
Tube complement (2 matched pairs) 6550C power output, (2) 6922 driver, (2) 6922 input
Other Maximum input: 3.5V RMS (volume-30dB or lower)
Dimensions 19" (48.3 cm) W x 7" (17.8 cm) H x 15" (38.1 cm) D. Handles extend 1.5" (3.8 cm) forward
Weight 43 lbs. (19.5 kg) Net; 56 lbs. (25.5 kg) Shipping.