The Sony SRF-AX15 is an AM stereo/FM stereo radio that's available only in Japan. I ordered mine several years ago from Audiocubes. The price appeared to have doubled since that time. At the time this article was revised in 2020, it did not seem to be available at all.
The SRF-AX15 is one of a few portables that Sony made only for the Japanese market. The Japanese culture is renowned for elegant design of small things, and the SRF-AX15's design benefits from that tradition.
Unlike most "Walkman" style radios, the SRF-AX15 has a speaker, which can be overriden by plugging headphones into the headphone jack on the left side of the radio. It's something of a throwback to the transistor radios of the 1950s and 1960s, though updated with stereo capability through the headphone jack. The AM tuning scale, using single-digit numbers rather than the full numeric frequency, is also something that you often see on older transistor radios.
The tuning range for the FM band is unusual. Because this radio is made for the domestic Japanese market, it has to tune the Japanese FM band. While almost all other technical specifications for Japanese FM radio are the same as for North American FM radio, the stations broadcast on a range of frequencies that's different: 76 to 90 MHz. There's a little overlap with the North American 88-108 MHz band. This radio covers both bands.
The "TV" numbers -- 1, 2, 3 -- were Japanese analog TV channels. They are placed in the same area of radio spectrum where the U.S. put FM stations. Fortunately, the Japanese analog TV system was exactly the same as the U.S. analog TV system, except for channel assignments, so the radio worked across the entire band. Without getting into an even longer description, suffice it to say that, for both FM and analog TV, the U.S. and Japanese standards were compatible.
As a consequence of the wider range of FM frequencies covered, tuning FM stations on this radio can be fussy. It's too easy to tune past the station that you want. More precision in tuning would have been helpful. It's the only ergonomic mistake this radio makes, though. The rest of the package is nicely designed and the construction quality is excellent.
A switch on the right side is for selecting AM or FM reception; a switch in a recessed area on the back selects stereo or mono operation. Unusually for a radio of this size, it has a telescoping antenna for FM. That's the silvery thing you see along the right side of the back of the radio. The black cord is a carrying cord that's built into the radio.
Having a telescoping FM antenna would normally be a good thing, but this radio's performance on FM is mediocre. While the radio has fewer problems with overloading from strong signals than most Sony FM Walkman radios have had, it appears to be less sensitive than most of them, too. I took it along on my trip to Australia in 2009 and found myself disappointed in its FM performance.
A Korean blogger, whose site I can't find any more, wrote in 2010 or so that the FM section in this radio was prone to damage from static electricity. That damage would cause the radio to become less sensitive than it should be. I wonder if that happened to mine. Sony portable FM radios generally are so-so, anyway, but when so many other aspects of the radio are done so well, it's puzzling to have FM performance that's so bad.
In 2020, on a trip to Sonoma, far enough from the center of the San Francisco metropolitan area to be challenging for FM reception, yet close enough that almost all San Francisco signals should be receivable, I found that the SRF-AX15's performance was subpar compared to the (generally very good) Sony SRF-40W, and definitely could not keep up with DSP-based radios. Its performance was most comparable to the SRF-A1 AM stereo/FM stereo Walkman, which is also a mediocre FM performer.
In 2022, I had a client in my consulting practice who was based in Portland, Oregon, so I was able to travel there every so often. Since KBPS(AM) is still broadcasting in stereo, I got a second SRF-AX15 (once one finally appeared on eBay) and was able to try it out further. I noticed that the FM performance on this second radio was also comparable to the SRF-A1, possibly with a little less front-end overload. The radio seemed more sensitive than the original model I bought, but it still had challenges with signals that didn't come from strong local stations. AM performance was similar to my first SRF-AX15. The performance discussion in the next paragraph is based on that first radio.
On AM, the SRF-AX15 generally seems to be a good performer. There's nothing exceptional, but, for an AM radio, it does a reasonable job. In mono, frequency response starts rolling off above 4 kHz; the upper limit for stereo operation appears to be higher, approximately 6.5 kHz, but without a local AM stereo station, I'm not able to reach a more definitive conclusion. I will say that, when AM stereo stations were still broadcasting in the Bay Area, this radio was able to get a clean signal from one station that did not sound good on any other AM stereo radio that I had.
Bottom line: I would pass on the SRF-AX15. If you want one, I'd recommend looking for it on auction sites rather than going to Audiocubes (which seems to be defunct anyway). They appear occasionally on eBay, often at rather inflated prices. If you're not in an area with AM stereo stations, you can do better with other radios even though this is such an attractively designed product.
Other AM stereo radios from Sony: SRF-A1 | SRF-A100 | SRF-42