Technics ST-600L FM/ AM Tuner

This is a pretty basic FM / AM tuner from the late 1980s. At this point the radio tuner had been condensed into a few chips with minimal supporting components, though more than you got with the last of the big-brand hi-fi tuners in the ‘2000s. It supports long wave (522 – 1611kHz 9kHz steps, or 530 -620kHz 10kHz steps) and medium wave (155 – 353kHz with 10kHz steps and 2kHz shift to 153 – 351kHz) AM bands, and FM (87 to 1058 mHz). You can easily change the stepping and shift in both AM bands by holding their respective controls for four seconds. This is supposed to be used depending on the region you’re in, but I’ve found it to be useful in tuning pirate stations especially at night.

Technics St 600l Front Main

The tuner has a 24-channel preset memory with supercapacitor backup. While the tuner is on mains power the primary side of the transformer is always live, and the microcontroller always powered to maintain the memory. When power is lost, the capacitor is specified to retain the memory for a week or so, and often much longer. You can name preset stations and overwrite the memory as desired.

Elsewhere you get selective stereo / mono listening and automatic or manual tuning. I’ve found the automatic tuning to be unusually sensitive, picking up weaker stations with ease. The tuner will fallback to mono reception in FM if the signal is weak, but on a good strong station reception in stereo is clean and dynamic with low noise. Despite being a later model tuner it’s no slouch, and demonstrates how good analogue radio broadcasting really is – better than digital in my ways.

Mine was immaculate in the original box and even included the original AM loop antenna, which is good as it connects via a two-pin PCB connector on the back which would be difficult to substitute. Some Technics tuner models had screw-terminal antenna connections, while most of their stereo receivers and later tuners used the same plug-in antenna. It seems they couldn’t make their mind up. I didn’t get the original FM wire antenna, but it’s just a standard 75Ω coax connector. Power is via a figure of eight cable as was typical of Technics equipment of the time.

Technics St 600l Inside 1

The only problem the tuner had was leaking capacitors in the power supply, evident as a nasty smell when the tuner had been on for a while. They were changed and full operation restored. The smell disappeared along with the transformer hum, though I still don’t choose to leave the tuner powered permanently.

Technics St 600l Inside 2

The alignment appeared perfect so I didn’t touch it, nor any of the components in the tuner circuit as all tested fine. A full service manual is available, though being a digital front end with quartz lock the alignment is greatly simplified over an analogue tuner. Still if it ain’t broke, don’t fix it.

Not much to say about this one, other than it is an excellent tuner that never seems to get a mention. Tuners in general are quite unpopular these days, and when they are brought up in conversation it tends to relate to the flagship models from the 1970s, arguably the golden age of analogue radio equipment. This humble late ‘80s tuner is a capable performer though, and a neat, discrete package that modestly hides its true colours. Guide price on the used market anywhere from free (or close to) to £20 for an immaculate example.

By Ashley

I founded Audio Appraisal a few years ago and continue to regularly update it with fresh content. An avid vinyl collector and coffee addict, I can often be found at a workbench tinkering with a faulty electronic device, tweaking a turntable to extract the last bit of detail from those tiny grooves in the plastic stuff, or relaxing in front of the hi-fi with a good album. A musician, occasional producer and sound engineer, other hobbies include software programming, web development, long walks and occasional DIY. Follow @ashleycox2

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