Truemors
This is one of the finest FM tuners I have ever had the pleasure to use; easily on a par with the best from Macintosh, Sansui and others I've owned. Produced during the late 1970's, the 2130 was the penultimate result of a specifications and fidelity war in the consumer tuner and receiver market. Marantz pretty much pulled out all the stops for this one, and you can hear it if you have a good FM station to listen to. Personally, I pipe Sirius satellite radio down some 75 ohm coax and have it hooked into every FM receiver in my home; keeps me from having to listen to the farm report and the other things my community (apparently) wants the station to play.
The oscilloscope on the left can display tuning (center and strength at the same time), multipath, and audio. In audio mode, the left and right channels drive the horizontal and vertical signals respectively, so a mono signal draws a 45 degree line and stereo signals draw various elliptical patterns. It's quite informative, you can see how much separation there is at any one moment, and any noise comes through as fuzz on the trace. For multipath, the scope makes antenna adjustment (beam FM antennas) 100% accurate, you can tell instantly when you've got the antenna pointed in the optimum direction. The scope also has external inputs so you can monitor audio from the rest of your stereo system. On the front, there are horizontal and vertical positioning controls and an external level adjust. On the rear deck are focus and brightness adjustments; I've never had to touch them.
Aside from the scope and its controls, the tuner provides controls for two IF bandwidths, switchable AFC ("Quartz Lock"), mono/stereo, muting level and output level, 400 Hz calibration tone for Dolby recording, high blend (multiplex noise filter) and switchable Dolby demodulation (the latter being useless to most people now, as no station uses this anymore... but I just happen to have a low-power ultra-hifi Dolby FM transmitter... :-)
The AFC switches off when you have your hand on the dial, so you can tune normally. It feels silky smooth, and the tuner's ability to separate stations makes tuning quite crisp when you're on-station. As soon as you take your fingers off the knob, the AFC locks back in (if you have it on, of course) and the scope shows the station perfectly centered. The lock LED shows that the AFC is operating.
The AM side of the tuner is pretty good, but not up to the standards of the FM side. Too bad; it's not all that difficult to make a good AM tuner, but very few manufacturers every paid proper attention to the problem in a consumer stereo context. One notable exception to that being Sanyo. Not that it matters anymore; quality AM broadcasting, sad to say, is dying. The airwaves are filled with talking heads. Babbling heads. Something like that.
From time to time, you can find 2130 tuners for sale on EBay. My advice is, if you like FM listening, grab one. They're incredibly underpriced. They generally go for $500 to $750, depending on condition; but you can't buy a comparably performing tuner today for under five grand, and even then, you won't get some of the amenities you get with one of these. No kidding. If you like FM, this baby is the brass ring.
