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Couple Tube questions

Leland47

Leland47

Super Member
:scratch2:

First...I've seen Magnavox branded 6BQ5 Tubes....Made in USA.....and Made in Great Britain....and tonight found some labeled as "Made in Japan."

I know Mullard made the British ones....but who made the Japanese ones?

There is a little emblem on the Japanese ones...its a circle with 4 compass points...and inside the circle, 2 parallel lines....and then another circle...with a dot in the center.

I'll try to get a pic of it.

Second...have some 1958 vintage Magnavox 6V6....and one, the glass is a bit loose. ( it works fine) Can I put a drop of crazy glue to stick the glass back to the Bakelite base? Or what is the best way to repair this?







:music:
 
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The emblem is most likely Hitachi. IIRC they used old Mullard tooling and are fairly decent tubes. I wouldn't hesitate to use them.

As for the loose base you can use super glue but it doesn't have sheer strength to handle rocking the tube when pulling it out of the socket. I use a 15 minute 2 part epoxy.
 
That is indeed a Hitatchi. They were on a joint venture with Philips early on...as the story goes, they later directly acquired tooling. Good stuff indeed.
cheers,
Douglas
 
I put crazy glue all around the base, after cleaning as much as possible,,, I try to rock them, and pull the by the base rather than the glass...
 
Super will work but about 10% of the time it can cause the tube to crack because it has no give and the bakelite and the glass expand at different rates .
I use speaker cone adheaseive or 3M weather strip cement for cars becaue it stay pliable .
 
Thanks for info...Great.

It was interesting to me...all 3 of these tube types are out of Magnavox amps. So I figured it was some sort of product sourcing situation.

But why....?

I guess Magnavox made millions of these consoles...so volume problem?
Or actually "giving" foreign companies business...."after the war?"

Or just sourcing for the cheapest price?

I can't imagine it was due to the likes or dislikes of the sound quality...as I do like all three brands of tubes...


On gluing the tube.....

I know epoxy can withstand very high temperatures....but is hard. It is also thick ....and I think a problem with flowing into that narrow space between base and glasss...

Crazy glue seems the easiest...but don't know about its temperature handling properties....but flows OK...and would go into that narrow space....

I like flexible....perhaps a clear silicon....flexible and can handle hi-temps....but doesn't flow into rim around tube...but could be pushed in with a small putty knife like tool.....

Have to cogitate....:scratch2:
 
I would suspect Magnavox back in the day just bought tubes from whom ever could supply the quantity at a good price when needed.
 
Indeed a lot of companies at the time bought tubes for the cheapest they could. Sometimes it just so happened Mullard or Amperex was that choice!

Kind of off topic but same went for a lot of different organ companies too. All the tubes would be USA made but the 12AX7's would all be amperex, think I ran into this "problem" with most wurlitzers.
 
Probably a case of who made the best price at that particular time. Likely they put contracts up for bid to supply some number of different tube types with the Magnavox logo printed on them. Whoever had the best price got the job for that batch.
 
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