[1BionicEar]

The 5963 is a premium version of the 12AU7 that was made in the late 1950s and early 1960s for computer use by industry and the military.
The blackplate versions are particularly well regarded.

One popular online tube seller describes them this way:
"A really fine blackplate from the 1950s, many audiophiles feel these outperform most of the other NOS 12AU7 tubes. $68 per pair. Out of Stock"

This is a special bunch, as they have long blackplates and Foil D getters identifying them as 1950s production.
I have a total of 8 RCA/GE tubes.  I describe them as RCA/GE because there was some cross-breeding going on here.
7 of the tubes have the iconic RCA stop sign model designation, even though some of them have GE logos and come in original GE boxes.
The 8th tube has the GE type 12AU7 model designation, even though  it has identical construction as the other 7.

All tubes test at 90% of new spec or better. 

I would love for somebody to scoop up all 8 of these as a bundle, and will adjust price accordingly.
Being more realistic, I am breaking them up as follows:

QUAD 1   $80
One tube has a partial GE logo and all 4 have the RCA 5963 in a stop sign designation.
Tubes come in 3 original GE boxes and 1 original RCA box.
Once again, these are all RCA blackplate tubes.







PAIR 1   $35
This pair has GE logos that are almost complete, even though they are clearly RCA tubes.
Generic white boxes.





PAIR 2   $20
This is a bit if a mix and match, but tubes have identical construction.
One tube has RCA style model designation and the other has GE style designation and a partial logo.
Generic white boxes.




Payment by PayPal Goods & Services.  I will pay the fees.
Shipping is $10 for USPS Priority Mail.

Let me know if you have any questions.

Thanks for your interest.