Japanese Tube Radio

[maxm]

I picked this set up over the weekend at a yard sale, we all know of the Japanese transistor radios, but there was also tube radios, mostly smaller AM radios that were sold under various brand names (the nameplate is missing from this set)
This look like an earlier radio, based on the styling and the fact that is still sues a point to point steel chassis, I was expecting a PC board in this little radio.

Some other interesting things that set it apart form its American made counterparts:
- The filter cap looks like a modern one, a metal tube covered in plastic, instead of an uncovered metal tube or a cardboard tube, it is also a clamp mounted cap, something I have only seen in older radios from the 30s.
- There is only one IF transformer on the top of the chassis
- All the resistors look like they are wire wound
- The tuning condenser and output transformer looks smaller than normal to me?
-This radio does use wax capacitors, but they look cheaper made than the American caps, they seem to be leaking much more wax than normal, and the paper is coming off some of them.

Just though I would share some observations on this set, since you don't see these too often, they were probably thrown out when they broke (this set was actually repaired at some time, the rectifier tube was replaced with a RCA)
I haven't powered this set up yet, but will soon, those bad looking wax caps will probably have to go though.

[Charlie]

Hey, I have two of those little sets! One carries a name brand of Invicta (i think) and i don't remember what the second one is. IIRC, they use AA5 tubes. The 35W4 and 35C5 tubes get pretty hot, and have created stress cracks in the cases because they are just barely below the top of the cabinet. I know that one if them actually works, but seems it needs something cause the audio starts to fade after 10 minutes or so.

Yes, the insides do look pretty cheesy, and the tiny chassis are kinda hard to work on. Guess i will have to get them out tomorrow and see if they still play.

[Chad Hauris]

I have one of these, it is a "Hi-Fi Master". Performance is good...the metal electrolytic cans used in Japanese sets still tend to be in good condition.
The IF circuitry cheats somehow...I think it uses an inductive coupled circuit with a single choke and capacitor to replace one of the traditional IF tranformers. There is a tiny schematic on the cabinet of mine that shows how it is wired but cannot remember exactly.

[maxm]

One question I forgot to ask...

In almost all the early electronics I have seen form Japan, the steel parts have this yellowish/goldish/greenish tint to them, as opposed to the regular silver/grey steel we see in American electronics. Is this some coating on the metal, or something form the manufacturing process?

[Sandy G]

Yeah, I've puzzled about that, too ! Must be some kind of chromate covering they use-but you're right-a LOT of the pieces parts have it on 'em. -Sandy G.

[Thatch_Ear]

Looks like the stuff labelled Monarch and Calrad which I think came out of the same plant as Kenwood/Trio/Realistic. That PS cap an Elna? Suzuki wire wounds?