[Nelco]

On the subject of 6BX7's a little while ago i purchased 3 Westinghouse branded tubes of this type for a modest sum. All tubes came in Blue and White Westinghouse branded boxes. One of the tubes seems to be a GE tube but the other two have no markings at all anywhere on the tube other than the Westinghouse branding / tube type on the base and I have no idea what they are so am hoping someone more knowledgeable can help identify them.

Tube no 1 has Halo getter support, double mica, non copper rods (steel?) and grey plates
Tube no 2 has Halo getter support, triple mica, copper rods and black plates


Tube no1

Tube no2

All thoughts gratefully received..............................

 

[gibosi]

On the subject of 6BX7's a little while ago i purchased 3 Westinghouse branded tubes of this type for a modest sum. All tubes came in Blue and White Westinghouse branded boxes. One of the tubes seems to be a GE tube but the other two have no markings at all anywhere on the tube other than the Westinghouse branding / tube type on the base and I have no idea what they are so am hoping someone more knowledgeable can help identify them.

Tube no 1 has Halo getter support, double mica, non copper rods (steel?) and grey plates
Tube no 2 has Halo getter support, triple mica, copper rods and black plates


Tube no1

Tube no2

All thoughts gratefully received..............................

Tube no1 is a later Tung-Sol. The earlier ones had black plates and mica spacers with 8 equally spaced teeth, top and bottom. And tube no2 is a Sylvania.

 

[Nelco]

Many thanks indeed Gibosi, much appreciated. Any idea as to a rough date of manufacture and why it would be completely unmarked by the original manufacturer?

 

[mordy]

Many thanks indeed Gibosi, much appreciated. Any idea as to a rough date of manufacture and why it would be completely unmarked by the original manufacturer?

Perhaps you can find some markings on the glass by looking carefully under good light and holding the tube at different angles?

 

[gibosi]

Many thanks indeed Gibosi, much appreciated. Any idea as to a rough date of manufacture and why it would be completely unmarked by the original manufacturer?

Westinghouse never made the 6BX7 and it would appear that it wasn't important to them to to date their rebrands. Further, many manufacturers used date codes that are largely indecipherable given that they were used primarily for warranty purposes. So often all we have to go on is the construction. Generally, halo getters were introduced around 1960. Further, Tung-Sol and RCA did not manufacture the 6BX7 until around 1960, so older ones, especially those with rectangular getters, were made elsewhere, usually GE and Sylvania, and simply rebranded. And then, having a bunch of Tung-Sol 6BX7, I know that that black plates are older than gray plates. But this pretty much sums up all I know. lol

 

[Nelco]

Perhaps you can find some markings on the glass by looking carefully under good light and holding the tube at different angles?

I did try with both white and UV light but i can't see any markings. I would have expected country of manufacture at least but nothing.

 

[Nelco]

Westinghouse never made the 6BX7 and it would appear that it wasn't important to them to to date their rebrands. Further, many manufacturers used date codes that are largely indecipherable given that they were used primarily for warranty purposes. So often all we have to go on is the construction. Generally, halo getters were introduced around 1960. Further, Tung-Sol and RCA did not manufacture the 6BX7 until around 1960, so older ones, especially those with rectangular getters, were made elsewhere, usually GE and Sylvania, and simply rebranded. And then, having a bunch of Tung-Sol 6BX7, I know that that black plates are older than gray plates. But this pretty much sums up all I know. lol

Many thanks for the insight, certainly a lot more than i knew
Knowing now that they are legit tubes and not likely to fry my equipment i swapped out the GE for the Sylvania. The GE had suddenly developed an extra smear of flabby bass between listening sessions. Not unpleasant but noticeable. Not sure if Tube just burned in now or degrading in some way. Anyway the Sylvania sounds very nice indeed, very similar tone to the GE but a touch clearer and bass now less flabby. Interestingly i also swapped the CIFTE 5Y3 GB coke bottle rectifier for a Phillips 5Y3 GB flat sided and this has made a big difference to the sound. Phillips tube much more transparent, less coloured and less pleasant sounding to my ears. Perhaps it will change over time but other 5Y3 GT tubes i've used i've not really been able to tell any difference between. Not so with the Phillips tube.

 

[mordy]

Many thanks for the insight, certainly a lot more than i knew
Knowing now that they are legit tubes and not likely to fry my equipment i swapped out the GE for the Sylvania. The GE had suddenly developed an extra smear of flabby bass between listening sessions. Not unpleasant but noticeable. Not sure if Tube just burned in now or degrading in some way. Anyway the Sylvania sounds very nice indeed, very similar tone to the GE but a touch clearer and bass now less flabby. Interestingly i also swapped the CIFTE 5Y3 GB coke bottle rectifier for a Phillips 5Y3 GB flat sided and this has made a big difference to the sound. Phillips tube much more transparent, less coloured and less pleasant sounding to my ears. Perhaps it will change over time but other 5Y3 GT tubes i've used i've not really been able to tell any difference between. Not so with the Phillips tube.

In terms of identifying tubes without markings I have found it useful to scroll through the offerings on eBay and look at the pictures for identification.
Another way is to go to Google Images and type in the tube designation - usually there are many pictures and links to websites together with the pictures and it can be very helpful as well.