Some questions about 6DN7s

[Jim R.]

I just got some tubes that I thought were Sylvania black plates but the tubes and boxes all say GE. Are these basically the same - I'm sure they are equivalent in sonics, but did one company make them for the other?

Also, how do you tell a black plate from a gray plate? Is the Black more like a very dark gray, and the gray a somewhat lighter gray? Is it pretty obvious.

These are all of identical construction, that, I know.

Thanks,

Jim

[mcandmar]

Have a look at the examples here http://bottlehead.com/smf/index.php?topic=5316.0

[Jim R.]

Well, if I weren't blind I would have looked it up. :-)

-- Jim

[mcandmar]

Ah right, sorry.   The sylvanias have a different internal construction from all the other tubes in that they have a tall thin plate for the first section, and the support micas have a different shape.

Of the regular GE and RCA tubes there are black plate and grey plate varieties. The black plates are a very dark almost shiny finish to them, and the greys are a light grey colour.  They are very different from one another.

Just to add to the confusion the Sylvania tubes were rebranded and sold under many different labels, so you can find RCA boxed and labeled tubes that are Sylvanias.

[Jim R.]

Thanks -- that helps -- All I know is that all 6 of these are of identical construction and all in GE boxes with GE labels, so probably not the sylvania black plates with the construction you first described.

I'm not going to worry about it -- I'm guessing there is really little difference in the sonics -- maybe a tiny bit here and there, but nothing I'm going to lose any sleep over. :-)

Thanks much,

Jim