The
Olson RA 581 was one of the most affordable tube receivers
available in the 1960s. It had only 11 electron tubes, no RIAA
preamplifier, no AM - only FM range. It did have a headphone
output with a loudspeaker switch and the option to choose the
column resistance of 4/8/16 ohms. The power amplifier could not
provide a lot of power because it was built on 6BM8 / ECL82 tubes
operating in the SE system. Power supply on a diode voltage
doubler. The tuning indicator is a magic eye. and there was no
stereo indicator. Interestingly, the MPX decoder was constructed
on a PCB. Apart from the tubes, there are also small, miniature
filters, evidently from transistor designs.