Socket for 5840 8 pin subminiature tube?

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rock soderstrom

Tour de France
Joined
Oct 14, 2009
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3,400
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Berlin
Hi folks,

there seem to be two types of 5840 tubes . One with flat terminal with long leads for direct soldering and one with short pins in cylindrical arrangement.

For the latter I am looking for a socket for PCB mounting. Does anyone know such a socket and has a supply source for it?

Cheers

20221015_215245.jpg
 
These aren't in stock any longer at Phil's Good Gear, but were listed a year ago or so. It might be worth reaching out to them, to see if they have a source (or some more that they would part with):

https://reverb.com/item/46763069-cinch-subminiature-5840-tube-sockets
Thank you, this is the first real proof that these sockets exist at all. :cool: My Google research had yielded nothing. It will not be easy to find a source for this. (on my side of the big pond)

I think I'll solder them right in after testing them in a makeshift jig with opamp sockets. A datasheet for the 5840 says you can't go below a minimum distance of 0.5cm from the glass body when doing this. That might just work...

Edit:

It seems to work. Telefunken USA does it the same way.

5840-4-scaled.jpg
 
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The 5840 was designed with soft wires for hard wiring into circuits. That was for reliability under high vibration and military use.
Completely unsuitable for a plug in socket.
 
The 5840 was designed with soft wires for hard wiring into circuits. That was for reliability under high vibration and military use.
Completely unsuitable for a plug in socket.
Sorry, that's not quite right. As I mentioned before, the 5840 comes in two versions.

With long leads to be soldered/welded directly into the circuit and with pre cut leads for use in sockets.

Screenshot 2022-10-16 at 11-25-45 Datenblatt 5840 Valvo.pdf.png

Quote from Valvo datasheet: "The tube is also available with connecting leads shortened to 4.7 - 5.4mm (basing E8-9) for socket B1 506 81."

That means this tube was also available with preconfigured leads for socket mounting.

Others had long leads and the user could also shorten them for socket mounting. They were not always hard soldered.

Screenshot 2022-10-16 at 11-32-59 CK5840 CK6205 - Datenblatt 5840 Raytheon www.tubedata.info ....png

I do agree with you wholeheartedly about one thing, though. For "under high vibration and military use", I would also prefer to solder them in. Even for my stationary mic preamp I will solder them in, only for testing sockets would be quite good.
 
harwin or keystone makes the contact pins and socket for DOA as well as ones that fit 12a_7 tubes--they likely make something that would work for this application. a custom pcb could be lower leakage than the cinch part.
the tfunkn usa carrier above is a slick idea too

a rough and ready test bed could be done with female header strip sockets tack soldered to a suitable copper clad board
 
If you (or anybody here for that matter) need sockets like this & they won't/can't send outside the USA, they can have them sent here in Denver, and I'll be glad to forward them over to you.

That said I like the header mounting solutions better than soldering in place - makes tube swapping just a little easier, haha!

(edit: needed more coffee)
 
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I bought a NOS lot of these on ebay years ago and built mics with socketed 5840 tubes. They worked great - makes it easy to check/swap 5840 tubes in a mic. Never had a problem operating the mics with them.
Watch for "subminiature tube sockets" on ebay or other places. I've never seen new manufactured versions, just NOS. There are a few with ridiculous prices on ebay now - not sure if they would still come up reasonably priced or not.
If you just need one I might be able to find one, I don't remember if I had any left
 
I bought a NOS lot of these on ebay years ago and built mics with socketed 5840 tubes. They worked great - makes it easy to check/swap 5840 tubes in a mic. Never had a problem operating the mics with them.
Watch for "subminiature tube sockets" on ebay or other places. I've never seen new manufactured versions, just NOS. There are a few with ridiculous prices on ebay now - not sure if they would still come up reasonably priced or not.
If you just need one I might be able to find one, I don't remember if I had any left
Oh, you’re the guy!

Kidding…but I expected there to still be a ton on eBay because some guy had so many of them for such a long time.
 
You can also scape the plating off the pins and solder wires to them, but that would defeat the whole purpose of what your trying to do so I'll shut up.
 
This is just an alternative mounting method, for the variant with leads. Pics are from a Duncan Twin Tube Classic; the tube is a subminiature dual triode. Not sure this is a useful method in a microphone application, due to possible transfer of external mechanical noise.
IMG_2224.JPG
These pedals are heavy, and sit on the floor of course; there are two 6021 (the other one's under the other side of the T bracket) so 4 stages of gain. It's not super easy to tube swap, but it can be done without removing the board.

IMG_2232.JPG
 
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