Japanese Tube Radio

[Celt]

Originally Posted by Jeffhs

BTW, I often wonder why those little 2-transistor sets had speakers; as I said above, they wouldn't work worth a plugged nickel unless you were close to at least one powerful station. These things may have produced enough volume for earphone listening (and probably did, with a strong local station), but how they could drive a speaker with only 2 transistors is way beyond me.

Quite simple Jeff. They were nothing more than a crystal radio with a two transistor amplifier in them!

[Jeffhs]

Originally Posted by CELT

Quite simple Jeff. They were nothing more than a crystal radio with a two transistor amplifier in them!

Gee, I never thought of that. No wonder they didn't work well unless you were practically in the shadows of your local station's antenna arrays. This explains why my Coronet 2-transistor portable worked so poorly in my area, which was some 30 miles from every Cleveland AM station. I got that little set from one of my cousins who was moving; he lived in an area where all the antenna arrays for the Cleveland stations are located, so the area had an abundance (some might call it an overabundance, especially in these days of cellular phone towers, pager transmission towers and the like) of very strong AM, FM and TV signals. (Someone here, can't remember who off the top of my head, recently mentioned that, because of the sheer number of AM/FM/TV/cell/pager towers in Cleveland and most major cities, these areas today are, or could be, considered "RF hell"; I believe it--it's even a problem out here in east-central Lake County, miles from the Cleveland stations' antenna farms, mainly because of cellular and pager transmitters, not necessarily broadcast station RF as we have only one small local station, as I mentioned above.) The radio worked well there for just that reason, but in my own area, as I said, 30-plus miles from every major Cleveland station, the most I could hear on the thing was a 0.5-kW station in the next town east of where I lived at the time. When that station went off the air at sunset (it was a daytime-only station then), I couldn't hear a darn thing on the Coronet radio. (The chances are, if I still had that set today, it wouldn't pick up much more than the 1kW day/0.5kW night local station five miles south of here, as well--the small town where I live now is much too far [45 miles] from the Cleveland stations for any kind of simple radio to work without an external antenna.)

An external antenna jack would have been a worthwhile addition to these small 2-transistor radios. This would enable the user to listen to the set even if he/she were in an area many miles from the nearest radio station, much like the external antenna connections on many AA5 table radios of 1950s vintage. Of course, that would eliminate the use of the radio as a portable, but really, what's the use of having a radio if you can't hear anything on it?

Which reminds me. I have a very good Zenith AM/FM radio here, 1963 vintage, which has terminals for an external FM antenna, but no such connections to allow the use of an external AM antenna. Zenith referred to these radios (and an older AM-only AA5 in my bedroom) as "Long Distance" receivers; how on earth did they expect the AM/FM set to live up to that claim on AM if it had no external antenna terminals? (The AM-only set in my bedroom does have external AM antenna terminals on the back cover, in addition to the loop antenna.) I am guessing it is simply because there were a larger number of low power, local-service stations in operation by the early sixties, even in small towns or suburban areas, thereby all but eliminating the need for outdoor AM antennas except for dyed-in-the-wool BC band DXers. Today, the expansion of the AM broadcast band to 1710 KHz and many formerly daytime-only local stations now operating full-time with lower night power and directional signal patterns have eliminated, for all intents and purposes, the need for external AM antennas with modern radios. Even automobile receivers work amazingly well (even in AM near-fringe areas like my town) with simple one-section rod antennas mounted near the left edge of the windshield (the rod being made of little more than a length of very stiff wire or thin metal shaft material, with a rubber or plastic tip at the top), not more than a foot or so in length. I see these short antennas on cars all the time; it never ceases to amaze me (even after 40 years of radio experimenting as a hobby, and 32 years as a ham radio operator) how well they work in most areas, but I guess that's progress for you.

Again, the abundance of radio stations these days, even in outlying areas, and the higher power of many stations (FM as well as AM), probably explains why small antennas on car radios and loopsticks/wire antennas/short whips on AM/FM portables work so well. I have a small, stick-shaped FM scanning radio with a belt clip that uses the headphone cord as an antenna; it gets almost every station I can hear on my home stereo setup and every other FM radio I own. Pretty amazing (IMO), when you consider most of the Cleveland FM stations are over 40 miles from here.

[bgadow]

Panasonic's logo used to be the word "Panasonic" inside the letter 'N', and some sets say National-Panasonic, others just Panasonic, others just National. Not sure why, maybe it changed through the years. In the later 80s I bought, at a freight salvage, a new National-Panasonic radio/cassette player. I can only assume it was for some market besides the US-maybe a gray market import? Anyhow, they had some pretty nice AM-FM table sets in the 60s, both tube & transistor. Maybe the best Japanese sets of that era I've seen. They don't have that cheap look of so many you see. Still make a good product, in my book. The cordless phone clipped to my pocket is amazing, especially given the abuse its taken.

[Jeffhs]

Originally Posted by bgadow

Panasonic's logo used to be the word "Panasonic" inside the letter 'N', and some sets say National-Panasonic, others just Panasonic, others just National. Not sure why, maybe it changed through the years. In the later 80s I bought, at a freight salvage, a new National-Panasonic radio/cassette player. I can only assume it was for some market besides the US-maybe a gray market import? Anyhow, they had some pretty nice AM-FM table sets in the 60s, both tube & transistor. Maybe the best Japanese sets of that era I've seen. They don't have that cheap look of so many you see. Still make a good product, in my book. The cordless phone clipped to my pocket is amazing, especially given the abuse its taken.

Gee, Bryan, I always thought only cell phones were small enough to be carried in or on a pocket; didn't realize cordless phones were that small these days as well. I have a cell phone that will fit in a pocket, but the handset for my cordless phone is much too big for that. I have a belt clip for it, but haven't used the clip yet because I don't need it; my apartment is small enough I can always go back into my bedroom and get the phone off the base when it rings, or if I'm expecting a call and I am watching TV, reading my paper, etc. I can keep the handset near my easy chair so I can lay hands on it in a hurry when the ringer goes off. Never had any need or use for the belt clip on that phone for just those reasons.

Your cordless must be built like a battleship if it can withstand so much abuse as you mentioned it has seen, and still work. I've seen and owned wired phones that break apart (literally) if dropped or slammed down on the cradle forcibly; a wired phone I brought with me from my former residence when I moved here got so noisy I had to get a new one (it had been noisy the last year or so I had it, but the problem went from bad to worse until I couldn't use it any longer; needless to say, it had to go). Oh well, I guess we should have seen this coming as soon as the Bell System broke up 20 years ago.

Cell phones can be like that too. My first cell was a Motorola V2397; it was built like a tank and could withstand any kind of abuse one could dish out. My present cell phone, OTOH, while still a Motorola, is built so cheaply and flimsily (thin plastic case) that one drop from any height will almost certainly ruin it in no time flat. The phone is cute, small, and works well for me (it gets reception just about anywhere and sounds good), but I do wish Moto would have built it as sturdy as my V2397 is. My present phone is a Moto 120T.

Oh well. I guess that's what we're getting from Japan and elsewhere in the Orient these days. National Panasonic radios must have been built very well, unlike the cheap things coming off assembly lines today. (I had a Panasonic AM/FM radio in the late '70s that never gave me five minutes worth of trouble; I am only sorry I got rid of it sometime in the early '80s, when I bought my first stereo system.)

[wa2ise]

That Japanese AA5 chassis looks a lot like one I have.
They are pretty cheesey.

[bgadow]

Jeff, that phone isn't real small but is rugged. I've dropped it on a concrete floor at least a dozen times. Its about 4 years old (or more) now with the same battery, still holds a charge for a week of use. Range is about 1/4 mile. Made in Japan, which is why its good. Hardly anything is made in Japan these days! I also have a 4 year old Panasonic VCR that was made in Japan, and aside from a minor problem that I think was caused by a lightning strike it works great.

[Jeffhs]

Originally Posted by Charlie

The tuning eye is a 12ZE8. I havent' found this number anywhere, and no substitutes. I'd like to get a fresh one as this one is very weak. If someone comes across a listing for this tube, please let me know.

Charlie,

I've never heard of a 12ZE8 magic-eye tube. The ones I remember are six-volt units; 6U5 and 6E5 come to mind. (There is also the EM84, which is a tuning-eye tube but the display is two bluish-green bars that indicate proper station tuning; these were mostly used in old Grundig and other makes of all-wave receivers of 1950s vintage.)

If you can't find a 12ZE8, perhaps you could rework the filament circuit (with a separate 6.3-volt transformer, and a resistor in place of the original tube's 12-volt filament so as not to upset the voltage drop across the heater string) to allow the use of one of the 6-volt eye tubes. There should be plenty of old 6U5's/6E5's around if you do a little looking, or if you have (or can find) a junker set with a good eye tube, that will work as well.

If your set's tube is getting dim, it is almost at the end of its life and should be replaced anyhow. Another dead giveaway that the eye tube is getting weak is if you see red splotches around the target electrode inside the tube, as you look straight at it. I don't know exactly how this ties in with a weak eye tube, i. e. what happens to the tube to cause the red tinge on the target element, but I remember reading in an old issue of Radio-Electronics magazine that this is one of the telltale signs that the tube is getting weak and is likely on its last legs. I remember reading in the same magazine that had this information one technician's story about a customer who brought in an old set to be repaired; she told him, "The radio works well enough, but the Magic Eye is all bloodshot!" Sure enough, when the technician turned the radio on to test it, he noticed a red tinge on the target electrode of the 6U5 eye tube as soon as the set warmed up. A new tube cleared up the problem, and when the tech tested the eye tube later on, yup, you guessed it, the cathode emission was much lower than normal.

Here is my Panasonic RE 777A multiplex stereo radio from the late 60's. I paid $12 for this one at a thrift. Heard it playing when I found it and it works like a charm. Sorry for the washed pics.

[Charlie]

RocknRoll,

That's a cool tube stereo! And for 12 bucks? Hell the 12AX7 in there is worth that alone!

Jeff,

This is the first time I've seen a 12zE8, but as Rocknroll pointed out in an earlier post, there are two TOYO branded 12ZE8's on ebay right now. So, if I don't forget about them, I'll either bid on these OR wait and see if any others come along that might be priced less.

6U5's are generally pretty expensive... 6E5's are a little less. Seems I recall that there are a few other 6?5 numbers for eye tubes listed in my old tester, although I've never seen those numbers in person. I'm not at home to check right now, but seems the number 6T5 comes to mind... but then I may be mistaken.

[maxm]

Here you go... All cleaned up and put back together...

[Sandy G]

Awrite Max ! That little guy looks good enuff to eat. Looks like its made outta caramel icing. -Sandy G.

[wa2ise]

While looking around at the web page
http://www.geocities.co.jp/Technopolis/1660/5zl-372.htm
I noticed a fair amount of their AA5s had earphone jacks
that could be plugged into a jack wired between the 12AV6
and the output tube (30A5 or 35C5). See diagram at the bottom of
this page. With the jack ground
tied to the powerline! They use 100VAC, but that's not
that different from 120VAC. Seems they didn't worry about
shock hazards back then.

[crooner]

The finest japanese radio I had was this one...

It's a "Delmonico" multi-band Grundig knockoff. It only resembles a German radio in cosmetics. The circuitry is all Japanese with American tube designations. Mine had all original Hitachi tubes and the speakers were Pioneer.

Even though it was mainly a tube radio, it had a built in Multiplex FM adapter that was solid-state. Main chassis was point to point wired but the adapter was built on a PCB.

Interesting set. Wish I had kept it!

[Sandy G]

Wow, Crooner, that thing fairly shouts "Grundig", doesn't it ? Yeah, too bad you still don't have it-that was a beauty.-Sandy G.

[asynchronousman]

Originally Posted by Jeffhs

...Oh well. I guess that's what we're getting from Japan and elsewhere in the Orient these days. National Panasonic radios must have been built very well, unlike the cheap things coming off assembly lines today. (I had a Panasonic AM/FM radio in the late '70s that never gave me five minutes worth of trouble; I am only sorry I got rid of it sometime in the early '80s, when I bought my first stereo system.)

I am buying a 7" National Panasonic b/w TV "Speed-O-Matic" in medium blue today. It still runs well except for the occasional diagonal bars and the CRT is awesome--$10 at my neighbor's. (Model AN-609D it turns out).

My Sansui SAX-200 has worked so well that I didn't notice until TODAY that it has NO pointer! Hmmmm. Hafta open it up and look.
---
Nope, sorry I found it but it's dark over on that side with no light there (guess that's been a Sansui problem longer than I thought). Later. Must rest.