Made in Great Britain Tubes

[SamBooka]

Silly question.
I have a few tubes that say this. "Made in Great Britain"
Someone told me they were Mullards because they were made in GB.
Surely there were other tube manufacturers in GB?

[scottl]

Yes... Many of these are Brimars in my experience. The Mullards will usually have the factory codes on them. I have a couple Brimars that say Made in Gt Britain without the Mullard codes.

Interestingly enough, I have an RCA labeled tube that says Made in Gt. Britain. However, it is a Tungsram!

Originally Posted by SamBooka

Silly question.
I have a few tubes that say this. "Made in Great Britain"
Someone told me they were Mullards because they were made in GB.
Surely there were other tube manufacturers in GB?

[scottl]

Go here for pictures of almost all NOS tubes.

http://www.tubemongerlib.com/gallery2/v/12AX7/

[Timbre Wolf]

Brimar, Ediswan (Mazda), GEC/Genelex, and Tungsram all made vacuum tubes in Gt. Britain at one time. Most modern guitar amps call for tubes that were only made by Mullard or Brimar, if they're truly of British origin. The Brimar tubes often say "England" on them.

The tricky thing comes when you've got tubes that were sold during the Cold War. During this time, British traders imported Eastern Bloc tubes (such as the Tungsram Scott mentions, above - which is not to be confused with older Tungsram tubes that were truly British-made) and re-labeled them for sale to the USA. This surreptitiously bypassed trade sanctions expressly prohibiting purchase/import of goods produced in Eastern Bloc countries. Many of those tubes are marked as being made in "England" rather than "Gt. Britain"

If that confusing history doesn't help, then there are other clues to be had by looking inside the glass (look within ). You can always post a clear photo for positive i.d.

- T

[SamBooka]

Well.. I bought 16 12AU7s.

One telefunken.. pretty sure of that... ugh.. you are going to make me take them out.

Before anyone gets excited, they are all used and untested but the guy I bought them from is pretty cool so even if there are a couple of duds the price was in my range.

1 - With short black plates. Square Getter.Unknown origin.
1 - long black plates. Not square but not round getter. "D getter?" Unknown origin
1 - Short grey plates. Made in Canada. Round Getter
1- long grey plates. Cant see the getter. Made in Canada
1- long black plates, square getter, labeled "AMERICAN, Made in USA" but that is probably the rebranded.
1 -long grey plates. Square getter. Unknown origin.
2 - Long grey plates. Round getters. Made in USA. Labled Sylvania in Green.
2 - Short grey plates. Round getter. Labled ROGERS (pat Canada) Made in Great Britain. (something B04)
1- Long Grey plates. Square Getter. Made in Great Britain (but printed like it was rebranded. 852 1022 158
1- Long grey plates. Round Getter. Telefunken lable. Made in Western Germany.

[Jimmy P]

Originally Posted by scottl

Go here for pictures of almost all NOS tubes.

http://www.tubemongerlib.com/gallery2/v/12AX7/

I can't believe I've never stumbled upon this site! What a great resource. Thanks!

[Timbre Wolf]

Originally Posted by SamBooka

Well.. I bought 16 12AU7s.

2 - Short grey plates. Round getter. Labled ROGERS (pat Canada) Made in Great Britain. (something B04)
1- Long Grey plates. Square Getter. Made in Great Britain (but printed like it was rebranded. 852 1022 158
1- Long grey plates. Round Getter. Telefunken lable. Made in Western Germany.

I abbreviated the list, because you started the thread with the Great Britain i.d. concept. The two short gray-plates with the "B04" are likely Mullard, Blackburn made, in 1960. The other Great Britain valve may also be a Mullard - look for the code beginning with "B" about in the same location as the first pair (these are called etched codes). Here is a good reference for you, for Philips etch codes: Tube Classics

The "Telefunken" will be easy to i.d.: look for a diamond shape embossed between the pins, on the bottom glass. Also, the round getter wire will be a slightly smaller diameter than others, with fatter cross-section to the wire.

I could take a stab at the others (like the first, with short black-plate may be a US-made 5814), but if you really want i.d. - please post a photo.

- T

[SamBooka]

Thanks All.

Two great sites for my book marks too. As I mentioned. Used tubes, dont even know if they work but I can live with that. I only needed 2 or 3 (and I am sure at least 3 of the 18 work).

[scottl]

What are you using 12AU7s for??

[Ginglymus]

Tubes branded as being made in GB are quite often be from factories outside the UK, and the reverse can also be true. You can find "Mullards" that were made in Holland, and Amperex-branded tubes that are actually Mullards in disguise, for example. The Philips-owned companies seem to have shared a lot of inventory prior to branding. And they sometimes outsourced to Eastern Europe, as Thom said. Even the internal features can be misleading. I have some EI 12AX7s that are branded "Seimens Made In Western Germany, but that look identical to Telefunken smooth plates minus the diamond.

This is a useful document for deciphering many of the etched codes:
http://eastwoodamps.com/PhilipsCodes.pdf

[pfflam]

Originally Posted by scottl

What are you using 12AU7s for??

My question exactly . . .


I have buckets-full of great black and gray plates 'made in USA' 12au7s . . . I don't know what to do with them and am too lazy to sell them.

[SamBooka]

Well I wanted to get one or two for reverb drivers. One or two to play with and a couple for a possible firefly build if I ever have time. The guy said he had 10-12 so I said might as well take them. He finally dug up 16 and a couple of 12ax's

I figure I have a lifetime supply now lol.

[mc5nrg]

12AU7s are common in some 70s tube Univox amps.

[TD_Madden]

Before I'd worry about their origin, I'd listen to how they sound in my amp.....

[ski_fast]

12AU7s work well in tube preamp pedals such as the Butler tube driver. With a 12AX7 some pedals have too much sizzle IMO but a 5751, 12AY7, or 12AU7 can tame it nicely. I wish I didn't sell my Budda pedal before trying this trick.

Trying and testing tubes with different gain structures (even different brands) is really the only way to adjust amps and pedals that have too much gain in a factory preset. Many of these can currently be purchased cheap. RCA blackplate 5963=12AU7, 6072=12AY7. The word is out on 5751s and they are being snapped up fast. Especially early Sylvania blackplates.