I found a 1972 catalog description of the AR Model R receiver
(It sold for $440 back then, including case) and here's how it
reads:
120 WATT SOLID-STATE STEREO FM RECEIVER
FET front end with 4-section capacitor, multisection crystal IF
filter, IC IF amplfiers, and 2uV sensitivity insure
superb FM reception. Power output: 60 watts rms @ 4 ohms.
Self-resetting thermostatic circuit breakers in both
channels, tape monitor and speaker-headphone switch. Outputs
for tape recorder, center channel, headphone and
4-16 ohm speakers. Size: 17-1/4" W x 6" H x 11
Phono/FM/Special selector knob (special is the same as AUX)
Ganged Bass and Treble tone controls (separate for left and
right channels)
Mono/Null/Stereo selector knob
Volume Control
Tuning Control
Normal/Tape Selector Switch
Normal/Hush Off Switch
Speakers/Headphones Selector Switch
Headphone Jack
In addition it has a center channel tuning meter and a stereo indicator
light.