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Analog Angle Blog

Old vs. New Transistor Radio Exemplifies Advances

An old — on second thought, make that “very old” — Sony AM/FM broadcast transistor, which I somehow acquired, finally got a little too cranky for me, Figure 1 . The analog-dial tuning knob was sluggish, the station-tuning repeatability across both AM and FM bands was degrading, and it ate costly 9 V batteries. For the past years, I used it only occasionally, as when I was outside on a project.

Figure 1

This 9-transistor Sony AM/FM radio is over 40 years old and still works, although tuning and audio quality are not as 'crisp' as they were decades ago. (Image source; RadioMuseum.org)

This 9-transistor Sony AM/FM radio is over 40 years old and still works, although tuning and audio quality are not as “crisp” as they were decades ago. (Image source; RadioMuseum.org)

Although I don’t like to discard old stuff that still sort-of works, it was time for the radio to go. First, of course, it needed a quick forensics review, so I opened it up – just two simple screws – and saw large discrete components (by our standards) including capacitors, inductors, ferrite rod antenna and, of course, transistors (nine of them), all on a single-side, low-cost phenolic circuit board. I did a quick web search and found that the unit dated back to around 1976, so we’re looking a unit that is over 40 years old and still works, although not as well as when new.

Among the many sites I found which called out this radio, was the Radio Museum, and it had some photos of the TFM-6100W which were better than the ones I took; see Figure 2 . I estimate the Sony radio, which measures about 6 × 3 1/2 × 1 ½ inches (15 × 9 × 4 cm), retailed for around $25 in 1970 dollars (and there are still some used ones for sale on eBay…go figure that one out!)

Figure 2

Inside the Sony TFM-6100W are nine transistors, assorted passive components, all discrete devices and mounted on a single-sided phenolic circuit board. (Image source; RadioMuseum.org)

Inside the Sony TFM-6100W are nine transistors, assorted passive components, all discrete devices and mounted on a single-sided phenolic circuit board. (Image source; RadioMuseum.org)

Flash forward to the present: I needed to purchase a replacement, and soon found a very nice AM/FM/SW (shortwave) radio online for about $15. This unit, a model L-258, Figure 3 , is sold under a variety of brand names, and I still can’t figure out who is the actual manufacturer (not that it matters). It’s about the size of the Sony unit, has synthesized digital tuning, channel memory, is USB-recharged, and even accepts a memory card so it can play MP3 recorded music. It’s about the same size as the Sony unit but somewhat lighter.

Figure 3

The multi-branded L-258 AM/FM/SW radio is the same size as the Sony unit, but is far cheaper while adding many digital and user-friendly features and capabilities. (Image source: aliexpress)

The multi-branded L-258 AM/FM/SW radio is the same size as the Sony unit, but is far cheaper while adding many digital and user-friendly features and capabilities. (Image source: aliexpress)

Now I have radio which not only offers basic AM/FM reception, but also does much more, with synthesized tuning and digital readout, for far less that I think that SONY unit cost back in the day – and all in a package about the same size. (side note: that old radio was well-built and has survived all sorts of abuse; that was back when Sony products were well-designed and built, a situation which substantially changed for the worse few years later, IMO.)

There’s an element of irony here. Broadcast radio (AM, FM, and even Short Wave {SW}) is not a growth area in terms of audience, especially with younger prospective listeners, and radio certainly doesn’t have the dominant share of mind and role it once had. Depending on which report you look at, AM/FM listenership is stagnant or shrinking (despite some framing of survey questions to get more favorable answers, IMO) see References , while credible data on the shortwave audience is just not available. Thus, while the audience is shrinking, the technology for bringing radio to the masses has improved dramatically in performance and cost. In fact, some of the newer cars don’t offer an AM radio even as an option, due to nasty EMI issues as well as lack of driver interest, see the Wall Street Journal article “Your Tesla Can Go Zero to 60 in 2.5 Seconds But Can’t Get AM Radio.”

In a way, that’s too bad. Despite its many limitations, broadcast radio is still the easiest and quickest way to reach millions, and the incremental sourcing cost of supporting additional users is zero, since the broadcaster doesn’t need additional infrastructure. Radio has also been a major driver of advances in receiver architectures and mass-market design and manufacturing, based on the single-conversion superheterodyne technique invented by Maj. E.H. Armstrong (he also developed the superregenerative receiver and FM radio!). The classic five-tube superhet design was a model for the transistor radio (same IF frequency, too), but is now being overtaken by direct-to-baseband, zero-IF approach.

In many ways, the basic transistor radio is a testament to the abilities of those engineers who figured out how to maximize use of discrete transistors and components despite their unavoidable shortcomings and “made it work.” It shows what innovation and persistence can accomplish with components and tools that are comparatively “stone age” compared to what we have now.

Are there any classic designs which you have studied, and which have impressed you with how they solved design and manufacturing problems? Are there old or even ancient products that you still actually use?

References

Radio Museum

Ad Age, “Radio’s health is better than you think, but what’s the long-term prognosis?

Inside Radio, “Who’s Listening? AM Radio By The Numbers

Nieman Lab, “AM/FM radio holds strong for American listeners

The Nielsen Company, “How America Listens: The American Audio Landscape

News Generation, “Radio Facts and Figures

Edison Research, “The Heavy Radio Listeners Report

Variety, “Traditional Radio Faces a Grim Future, New Study Says

Digital Music News, “Radio Is Dead In 10 Years. This Study Proves It

Soundscapes, “Audience research for shortwave broadcasters

Related Content

AM Radio: The Beat Goes On (for a Little Bit Longer)

Should We Care if AM Radio Fades Out?

Is the End in Sight for Analog FM Radio?

The Final Knock-Down for Auto AM Radio?

1 comment on “Old vs. New Transistor Radio Exemplifies Advances

  1. RituGupta
    April 11, 2019

    I actually have several of these vintage radios at home. It is not that I still use them because I can easily listen to any stations from the comfort of my bed with my radio app on the cellphone. However, they are a precious memoir that are great conversation starters especially with the younger generation.

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