This little Pioneer SX-580 was the bottom of the line from Pioneer around 1979. It only produces 20 watts per channel and has minimal features. Still, it's a good little receiver for an entry level unit. It's not going to be enough to power large speakers but for a garage or small room it could work well. I believe they retailed for about $250 when new.
As you can see they have the stereotypical look of late 70's Pioneer receivers with the silver face and white dial. Pioneer also produced the SX-590 which was essentially the same receiver only with a black dial face.
The SX-580is fairly small at 17.5" x 12.5" x 5.25" and weighs in at just over 18 pounds. If you need a service manual you can find it at HiFiEngine.
Looks good with the lights off and the dial lit doesn't it? The white dial face and amber lighting give it a sophisticated look.
The Pioneer SX-580 came out just near the end of the hi fi boom in the late 1970's. The build quality for these units was still good and their performance excellent. During the following years cost cutting measures resulted in lesser quality units.
Purchasing an SX-580 isn't going to break the bank. A lot of them were made and collectors tend to avoid entry level units so prices are pretty reasonable. If you just need a small receiver with a little power then the SX-580 might work for you. A nice and clean,m serviced unit will run about $150 with average working units running about $100.