audio research
DUAL 51

Description
Tube stereo power amplifier.

Introduced
1972

Discontinued
1977

Revisions
-

Options
Gold/champagne faceplate

MSRP (US new retail)
$695. Later increased to $895.

Specifications

Power output 50 Watts per channel minimum RMS into a 4, 8, or 16 ohm load from 20 Hz to 15 KHz with less than 1% total harmonic distortion.
Power bandwidth 15 Hz - 30 kHz
Frequency response  
Input sensitivity 1.5 volts for rated output.
Input impedance 80K ohms at 20 Hz; 30 K ohms at 15kHz.
Output taps 4, 8, 16 ohms.
Output regulation  
Overall negative feedback  
Damping factor 14 at 8 ohms (1 kHz).
Distortion THD .1% @ 1 kHz, .5% @ 30Hz, < 1% @ 15 kHz. Intermodulation distortion less than .5% at rated power.
Slew rate  
Rise time  
Hum & noise More then 80dB below rated output.
Power supply energy storage  
Power requirements  
Tube complement (4)12AX7, (8) 6FQ7, (2 matched pairs) 6550, (1) 6550
Other  
Dimensions 19"W x 12 1/4"D x 7 1/2"H.
Weight 50 lbs.

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