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 Post subject: Novar vs Magnoval Vacuum Tube Sockets
PostPosted: Feb Thu 17, 2011 8:19 pm 
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Location: Oswego, NY, USA
I don't understand how some internet vendors & Ebay sellers advertise their 9-pin sockets as combination Magnoval/Novar, inferring that the same socket handles either tube base. The (U.S.) Novar tubes have .038"/1.02mm dia. pins, while (European) Magnoval tubes have much thicker .046"/1.27mm dia pins. I thought that inserting a Magnoval tube into a Novar socket destroys the socket (springs the contacts). In fact, the late-style Eico 667 tube-tester (the panel without a roller chart but more sockets) & Heathkit TT1 & Triplett 3444 & Hickoks have separate Novar and Magnoval sockets on their panels; and whenever I've tried inserting a Novar tube into a Magnoval socket, the fit is very loose. What am I missing here?


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 Post subject:
PostPosted: Feb Fri 18, 2011 12:55 am 
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Location: British Columbia
I have had no problems inserting el509's into the American sockets. Infact I prefer it. el509's get really hot in modulator service (1000 Volts on the plate and 25mA static idle current.) The sockets at first are tight (first install) after that they remain very tight under service. The pins don't seem to loose their tension. (even after years of service)
As for the other way around, I have not done that.


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 Post subject:
PostPosted: Feb Fri 18, 2011 1:07 am 
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I tested a Magnoval tube in one of my tube testers. The Novar tube socket was never the same. I have to replace it now because I can't test tubes reliably in it. So, I tend to agree...

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 Post subject:
PostPosted: Feb Fri 18, 2011 2:37 am 
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You can use a Novar socket for a Magnoval, as long as you never want to use it for a Novar again because the contacts will be permanently stretched out.

You cannot use a Magnoval socket for a Novar, it doesn't make good contact.

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Experience is what you gain when the results aren't what you were expecting.


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 Post subject:
PostPosted: Feb Fri 18, 2011 4:32 pm 
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Mr. Detrola wrote:
You can use a Novar socket for a Magnoval, as long as you never want to use it for a Novar again because the contacts will be permanently stretched out.

You cannot use a Magnoval socket for a Novar, it doesn't make good contact.


Exactly, well spoken...

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 Post subject:
PostPosted: Feb Fri 18, 2011 8:22 pm 
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Yep, got a tester where that had been done. Had to replace the socket.
What a job.

Gene

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 Post subject:
PostPosted: Feb Fri 18, 2011 9:21 pm 
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Makes me glad my collector interest falls off around 1960.


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 Post subject:
PostPosted: Feb Fri 18, 2011 11:57 pm 
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David Roper wrote:
Makes me glad my collector interest falls off around 1960.


Because of the diameter of tube pins?


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 Post subject:
PostPosted: Feb Sat 19, 2011 3:38 pm 
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I've had the same experience as the others, the Novar socket in my B&K-707 is loose as a back street hooker, can't test a 6JE6, 7868 etc without holding the tube at a angle... I have a new socket, but since I seldom need to test a Novar, just been lazy...

There were Magnoval to Novar adapters marketed years ago but of course are long since out of production...

Image

Tom


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 Post subject:
PostPosted: Feb Sat 19, 2011 6:02 pm 
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35Z5 wrote:
I've had the same experience as the others, the Novar socket in my B&K-707 is loose as a back street hooker, can't test a 6JE6, 7868 etc without holding the tube at a angle... I have a new socket, but since I seldom need to test a Novar, just been lazy...

There were Magnoval to Novar adapters marketed years ago but of course are long since out of production...

Image

Tom


Tom,

I didn't know that they made such a thing but I am not surprised. That would certainly be a solution wouldn't it?

And since I ruined the Novar socket in one of my tube testers, I have to hold the tube to the side as well. I have a new socket. But I am sure that the experience of changing it will reflect what Gene said :wink:

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 Post subject:
PostPosted: Feb Sat 19, 2011 9:04 pm 
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Sometimes the contacts can be re-tensioned enough to make the socket semi-usable... Applying pressure to to the outside of each side of the contact, using a small pick will usually do the trick...

My 707 is a later model, built in '72 and appears to have been used very little, but was in service long enough for someone to stick a Magnoval in it...

Tom


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 Post subject:
PostPosted: Feb Sat 19, 2011 9:25 pm 
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Location: Twin Cities, MN
Can someone post pictures of these tubes\sockets?

(for educational purposes)


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 Post subject:
PostPosted: Feb Sun 20, 2011 4:05 am 
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Location: SoCal
Hey guys:

Thanks for the info! Just what I needed. Gotta love that internet! I'm cataloging a bunch of old tubes (getting ready to test them), and I'm including the socket type in my database. I knew what a Novar was, and just handled a couple (used to service color TV's back in the day). Then I pulled one out that looked a little "funny"! Can't believe I noticed the difference. Probably wouldn't have if more time between the two had slipped by. Pulled up the spec for the 6EC4 / EY500A, and sure enough - "Magnoval". What the heck? Now I know! :D I need to test it eventually, I hope - shoot! That's another whole issue.

I'll see if I can get some decent pics and post them, but it would be really hard to tell the difference without a caliper on them (possible....). Still surprised I noticed the difference in my hands!

--Klemmer
(newbie here)


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 Post subject:
PostPosted: Feb Sun 20, 2011 8:19 pm 
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Here's a pic of the two pins. Magnoval on the left, Novar on the right. If you have both tubes, it's obvious.

Image

Full size & resolution pic here: Magnoval vs novar

Otherwise, I guess:
1) Check the data sheet (e.g. http://frank.pocnet.net)
2) Use a good caliper or micrometer & check the pin diameter
Novar pins = 0.038"/1.02mm
Magnoval pins = .046"/1.27mm
3) Try your novar socket carefully and don't wreck it
4) Buy a Magnoval socket and use it as a gauge?

Klemmer


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 Post subject:
PostPosted: Feb Sun 20, 2011 8:23 pm 
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AND just to complicate things further:
Remember that the official name of what most people call a "9 pin miniature" is (was?) actually "noval". Sheesh....


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 Post subject:
PostPosted: Feb Mon 21, 2011 1:05 am 
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Well, you guys covered it. I only wish I had taken the time to be more observant when I intended to test that Horizontal Output tube. It was a good tube but one tube tester of mine no longer provides a "tight-fit :wink: "

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 Post subject:
PostPosted: Feb Mon 21, 2011 1:08 am 
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Don

Most of us have done the same.. Good thing I don't test many of the heavy pin tubes...

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 Post subject:
PostPosted: Feb Mon 21, 2011 1:22 am 
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Norm Leal wrote:
Don

Most of us have done the same.. Good thing I don't test many of the heavy pin tubes...


Norm,

You only do it once! One day, I will get off of my fat arse and replace the socket. I have a new one. But if you have ever worked on a tube tester, you know it can get ugly.

Thanks,

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 Post subject:
PostPosted: Feb Mon 21, 2011 1:33 am 
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Location: Twin Cities, MN
What are some common numbers of magnoval tubes?

Are they all "European" numbers?


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 Post subject:
PostPosted: Feb Mon 21, 2011 3:06 am 
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ksk:

Not always Euro numbered. For example, I've got these Magnovals:
CEC4 (EY500A) - dual marked
25KQ6 (PL521 - dual marked
25HX5 - no Euro number, just the US one.

If I didn't have a Magnoval tube to compare against, I would buy a Magnoval socket to test any large 9 pin in first. If it's loose as a goose, you're good to go. If it's snug, keep it away from your Novar socket.

(there's some good lines possible in there, but I resisted :roll: :roll: )

-Klemmer


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