The Pioneer SX-737 was a mid to higher end stereo in their lineup of the SX-424, SX-535, SX-636, SX-737, SX-838 receivers. Produced in 1974 it churns out 35 watts per channel. Pioneer advertised it by saying: It has the power to do the job - not too much and not too little. That about sums it up. It retailed for about $300.
The SX-737 really is a nice looking receiver. The blue dial light and meter are accented by red and green indicator lights. Add in the wood cabinet and brushed aluminum face plate and it exudes that vintage audio look.
It has the usual array of features one would expect in a mid range stereo. The FM front end is equipped with a frequency-linear 4-gang variable capacitor and dual-gate MOS FET. FM reception stability is enhanced by its multiplex demodulator with the Pioneer's PLL (Phase Lock Loop) circuit.
One interesting feature of the SX-737 that you don't see on many other receiver of the time is the Recording Selector option that allows the user to record an FM station while simultaneously listening to an LP, or vice versa. The build quality of the SX-737 was good but they are known for blowing output transistors occasionally. Over 40 years after it was introduced they usually need some of the electrolytic capacitors replaced in order to function as they should.
Pioneer receivers are always popular and the SX-737 is no exception. They sold quite a few of them so they aren't rare. But, the desirable mix of aesthetics and performance make it a good receiver for vintage audio enthusiasts. A really nice, serviced, fully functioning SX-737 will sell for about $250 to $300. But, an average good working unit can be had for $150 or so.