Help Identify 6BQ5's

[63pontiacgp]

These test good as 6BQ5's. No markings at all other than a B on the bottom of 1 and an E on the other. Any idea on manufacture. Pulled from Silvertone (Sears) console.

Mike

 

[Tom Bavis]

Mullards get smokey like that... Look near the bottom for an etched code starting with "B".

 

[Hi-FiGuy]

Those look like Mullards to me. May be Japanese Mullards last of the production.

 

[Thocom]

My first thought was Mullard, that black tar substance seems to be common with them.

 

[byoungman1]

That "B" = Mullard's Blackburn factory.
I'm going to start an all-inclusive "Tube ID thread" here soon to cover things such as this...

 

[Andyman]

Yep.

look for acid etched markings on the lower half of the tube. The first will be 3 characters something like rx3 or the like and the next will be 3 or 4 like B6C or B6C4 which means Blackburn 19x6 March (3rd month) and 4th week if they are 4

Read this...

http://www.audiotubes.com/mullcode.htm

 

[mpholland]

Don't recall ever seeing a tube like this. Most of the old D getters I've seen were 50's euro tubes. Amperex, Mullard, Philips, etc. All of them that I have seen had a rectangular hole in the center. All of the round hole ones I have seen had halo or disc type getters. Any of those I mentioned should have acid etching also. This one does seem a bit of an odd one to me, although I think that the smoke/tar definitely is a sign pointing in that direction.

 

[markshan]

The wealth of knowledge on the site never ceases to amaze me.

 

[Leland47]

These test good as 6BQ5's. No markings at all other than a B on the bottom of 1 and an E on the other. Any idea on manufacture. Pulled from Silvertone (Sears) console.

Mike

From what I've seen, Silvertone amps used Silvertone labeled tubes.

Above info is great about where they came from...

 

[analog addict]

The rounded plate is something that makes me think Toshiba. The D getter is early manufacture, usually late 50'....

 

[heyraz]

While most of my Mullard 6BQ5's have a halo getter, I have one with a D getter like yours which I believe is rare.
I have many Amperex 6BQ5's with D getters but they aren't smokey.
The only other smokey 6BQ5's I have are Soviet but they have a disc getter.
You can "huff" a humid breath on a tube to make the faded print easier to read. Just like when you moisten a pair of eyeglasses with your breath to clean them. You might have to roll the tube in a strong light to catch the image.
Also check between the pins for any markings.

 

[63pontiacgp]

I've tried even a magnifying glass and the only markings I can find are the B & E marks on the bottoms. A buddy of mind was cleaning out a foreclosed home and pulled them out a Silvertone console that was in the backyard. Looked like it had been in the weather for a long time.

Mike

 

[63pontiacgp]

I can't get a picture of it but I found "B8D" acid etched in to each of them.

Mike

Yep.

look for acid etched markings on the lower half of the tube. The first will be 3 characters something like rx3 or the like and the next will be 3 or 4 like B6C or B6C4 which means Blackburn 19x6 March (3rd month) and 4th week if they are 4

Read this...

http://www.audiotubes.com/mullcode.htm

 

[63pontiacgp]

So........Blackburn, 1958, April?

Mike

 

[heyraz]

Looks a lot like my smokey Mullard with the D getter. My tube has 7 over 5 cast into the base and B8F etched into the glass.

 

[kvflyer]

Smoky tar-like deposits are often seen in Mullard 6BQ5/EL84 tubes. One question since I don't have a Mullard tube near by, "Did Mullard use a round or square hole in the plate"?

 

[heyraz]

Round hole. Plates have 3 crimps.

 

[Cadillac Kid]

That "B" = Mullard's Blackburn factory.
I'm going to start an all-inclusive "Tube ID thread" here soon to cover things such as this...

:thmbsp: