Acorn valve holders

[trh01uk]

Having just retrieved a number of used acorn valve holders from my bin for a member desperate to find some of these rare beasts, I thought it worth posting a tip for anyone else looking for these.

While checking out acorn valve holders on the net, I found someone selling NOS ones on Etsy - £4.90 each plus postage. I won't give a link to these, as I presume the same rules apply here to Etsy as to Ebay - but they were easy to find, without really trying.


Richard

[Bazz4CQJ]

It may be worth pointing out that those Acorn holders could be tricky things to use. Some care was needed or else a valve could be broken while inserting or removing it.

I made up a "jig" using a B9A valve base to enable me to connect Acorns up to my Avo valve tester, with leads terminated in a small coil-like winding to slip on to the Acorn pins, and that worked quite well.

IIRC, the Acorn pins are made of a copper alloy and it not uncommon to find they have oxidised and, in bad cases, the oxide gets under the glass and the seal can be lost. You can solder on to the Acorn pins, but it's best done with a hot iron and get in and out nice and quick. Practicing on a valve which has already lost its vacuum is useful.

B

[David G4EBT]

Yes - the Etsy ones are easy to find.

As Barrie says, the valve needs to be inserted with care, with the pressure applied to the pins to push them into the clips - not by pushing the valve itself down into the holder, which is unlikely to end well.

This earlier forum thread might be of interest:

https://www.vintage-radio.net/forum/...d.php?t=135587

And this forum thread by retired dormant member 'Variometer' on his splendid 'Acorn 1' receiver with a neat homebrew valveholder:

https://www.vintage-radio.net/forum/...ad.php?t=29513

Also, these links:

http://www.r-type.org/addtext/add152.htm

Article entitled 'Acorn Antiques' by forum member Stef Niewiadomski who will be well known to BVWS members from his many Bulletin articles:

http://www.r-type.org/articles/art-151.htm

'Using the 954 and 955 Acorn Valves in Shortwave Receivers'

http://vintageradio.me.uk/radconnav/acorn.htm

Remarkable valves which must have posed many challenges to design and manufacture, but made in their millions.
Rather a pity that more care wasn't used in designing a better valveholder. (There was another 'clamp' style design).

Hope that's of interest.

[Bazz4CQJ]

Originally Posted by David G4EBT

Remarkable valves which must have posed many challenges to design and manufacture, but made in their millions.
Rather a pity that more care wasn't used in designing a better valveholder. (There was another 'clamp' style design).

Hope that's of interest.

Yes, I've always had a soft spot for Acorns. They were pretty clever for the time they were designed and I seem to recall one of their primary uses was for VHF/UHF walky-talkies in the Pacific war? And then they found use in the US Army's GDO (cannot recall the name of that, but it was a damn good GDO). For anyone who wants to make a valve receiver, with the valves open to view, they would make a good choice as the heater seems to be lit up and visible to a greater degree than many/most other valves.

B