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Tube bases and plate caps rant

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HI!

OKAY, I'm half a century old now and I started out fixing tube stuff but been away from it for a long time.

I'm really only interested in the all glass tubes I have seen.

Can anyone tell me why 7 and 9 pin miniature tubbes have .040" pins?
Thats so close to 1mm. where they developed in otside of the U.S.A.?

I read that MAGNOVAL's were developed by Western Electric aroud 1956 and use .050" pins (both 'merican).

NOVARS's are the same except they hav .040 (1mm) pins. Did they come after MAGNOVAL's?

The connector on the top of a tube is caled a "Plate Cap".

The thing you need to atach it physically and electrically is called a "Plate Cap".

Tube Data Sheets I have looked at show mostly "Miniature Skirted Caps" and "Small Caps".

The web sites that sell plate Caps sell "small" "medium" and "large".

Now I think I need "small" plate cap (connectors) to fit the "miniature" plate caps on the tubes I have.

And I know the MAGNOVAL tubes I have will fit into the "9-pin-compactron" sockets I have (even though there is no such thing as a 9-pin-compactron) but after doing that a NOVAR tube will not fit because the socket will be expanded by the .050" pins and be to loose for .040" pins.

Took me about 2 months to 'figer' this out!

Hope it helps, would like to here from anyone whe been there and beyonde.

Jim
 
A 6GF7 is a perfect example of a 9-pin compactron - there are many others, and they are far more common than the magnoval tubes -a good tube manual will show you. The Chinese "small" plate caps are not well suited for the skirted caps common on many of the smaller compactron sweep tubes (and some octals) - they sit up high and look dorky, if they fit at all. At one time, there were bakelite tube caps available that addressed this, but I've never seen any of them on the NOS market. The big compactron sweep tubes take a "medium" cap, as far as I've seen, though most of the new Chinese medium caps are a P**s-poor (loose) fit, and the contacts fall out at the drop of a hat. The old Millen and National caps are much nicer if you can find them.

If you look carefully, you can find sockets specifically for Magnoval tubes. I have no Idea how they came up with the standards for pin size - I just scramble to find sockets that fit.
 
though there is no such thing as a 9-pin-compactron........A 6GF7 is a perfect example of a 9-pin compactron

Who is right here? Both people are.

GE registered the name "Compactron" to refer to their new 12 pin multiple section tubes. If you look through the GE literature you will find that there are no 9 pin compactrons. Since GE owned the trademark you won't find any "Compactrons" in the RCA tube manual. RCA called them duodecars. Tung Sol used the Compactron name.

I was working in a TV repair shop through my high school years (1967 - 1970) and we (and just about anyone else) referred to all of these new funny looking baseless tubes as "Compcatrons". That practice was adopted by the electronics magazines and GE did nothing to stop it so the name stuck.

It was also common practice for tube manufacturers to make tubes for each other so it is possible to find a tube with the word Compactron printed on it and a brand name other tham GE. I don't believe that I have ever seen the word Compactron printed on a 9 pin tube though.
 
You can see the metal pate cap skirt below the ceramic plate cap - dorky - the equivalent of "flood" pants in electronics. Plus, I've found the new build Chinese plate caps just don't grip all that well. The "large" caps may be better, as they made some attempt to duplicate the 4-point contact of the NOS caps. I'll try one on an 813 and see...
 
You can see the metal pate cap skirt below the ceramic plate cap - dorky - the equivalent of "flood" pants in electronics. Plus, I've found the new build Chinese plate caps just don't grip all that well. The "large" caps may be better, as they made some attempt to duplicate the 4-point contact of the NOS caps. I'll try one on an 813 and see...

I got some of the large ones for a couple of 812A that I have and they fit great - the first time. Second fit is looser, which is worrying. Obviously the material in the sprung part is made of too soft metal.
In my corner of the world, they are all that is available :mad:

Gary
 
You can see the metal pate cap skirt below the ceramic plate cap - dorky - the equivalent of "flood" pants in electronics.

HAHA! dorky will be OK for this time. I just want to make something (different) with tubes. The tubes I got are 29KQ6/PL521's. They have some interesting characteristics like 29V 300mA heaters and +-240V heater to cathode. I can string 4 of them in series and not need a heater trandformer.
Paid $10 for 10 tubes so I can afford to experiment. HECK, I only got a DMM and a soldering iron 2-3 months ago.

Jim
 
What really bugs me is that the metal contacts on the small and medium plate caps often fall out and get lost before you can use them - not exactly a ringing endorsement. I use NOS or UOS caps when I can because of this and the loose (and ever loosening) fit. I'm looking to use some kind of fuse clip for the the small-sized caps, though it will force me to machine some sort of shroud to cover the contacts.

This issue is why I haven't been really eager to start on my SE screen-driven 6P45s amp.
 
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What really bugs me is that the metal contacts on the small and medium plate caps often fall out and get lost before you can use them - not exactly a ringing endorsement. I use NOS or UOS caps when I can because of this and the loose (and ever loosening) fit. I'm looking to use some kind of fuse clip for the the small-sized caps, though it will force me to machine some sort of shroud to cover the contacts.

This issue is why I haven't been really eager to start on my SE screen-driven 6P45s amp.

Fuse clips, there's a possibility. Check out the places that sell big car audio stuff. I'll bet you will find gold or silver plated ones up to at least 1/2".
And for a shroud, again from the auto electrical world there are boots designed to fit over ignition coil pack input leads, and alternator leads to keep moisture out (and mechanic's spanners!). Not designed for HV use, so would have to be insulation tested, but they are designed for hot engine areas. They are soft (silicone?), so would snug down on the tube nicely.
 
This issue is why I haven't been really eager to start on my SE screen-driven 6P45s amp.

Never heard of a 6P45S so I googled it. 6P45S/EL509/6KG6
I really don't get the SE thing but I can see that LOTS of people do.
I was searching today and ran across the J J Electronics EL509.
Looks to me like a sweep tube stuffed into an octal based bottle.
Don't have a link, sorry. Are you a machinist? (been there)

Jim
 
The NOS Russian ceramic types are a bit expensive at ~$4 each, but they look well-made.

I don't have a problem with the way the tubes I have fit into the sockets but the way the socket mounts to the chassis is a little dorky. Nuts won't fit into the metal craddle so if you want the nuts underneeth you have to put the craddle on top. Or you need some 1/4" O.D. X 1/4" long spacers and the only thing the local hardware store sells is nylon or aluminum.
I searched for NOS Russian sockets and the best I could find was NOS USA's at Pacific T. V. in Canada but they only have 4 in stock. They do have new Chinese ceramic Magnoval's that look better than what I have. They also have plate caps and they describe size in inches so it's les confusing. I'm not interested in teflon and gold for a prototype.

Jim
 
Search for "EL509 sockets", and you'll find the all-ceramic Russian NOS types.

Yeah I have seen those. Looks to fragile. I will go with cheap and dorky. I could have made all the 1/4" 1/4" spaceres I'd ever need out of scrap TG&P stainless at my last job.
Next is how to make a 1 1/16" (actually 1.050") hole in whatever I pick for the prototype chassis

Jim
 
I'm looking at one in my hand as I write this, and they look solid, I just wouldn't tighten down on the mounting screws without a plastic washer to take up the strain a bit. The contacts are much thicker than the flimsy stuff used in most of the new sockets. I'll probably be using these with my EL509 SE amp.
 
Tube Amp Doctor (in Germany?) sells exactly what I have for 2.200 Euros.
They call them 9 pin Magnoval's. The EL509 PL509 EL519 PL519 seems to be the tube of choice for plasma tweeters. Now I have another project to work on but it will use the same tubes and sockets I already have and can get more cheap.

Jim
 
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