[rpf]

Also the 6P3S is not exactly the same as - and not as good as - the 6P3S-E.

[Tyson]

Hmmm, I have a set of 6 Russian 6P3S-E tubes I bought about a decade ago.  They've just been sitting in my tube box collecting dust, maybe I should give them a shot.

[jbryngelson]

UPDATE on the Journey:  I received my amp with Groove-Tube 6550 tubes and put it in my system.  It sounded great, but like many I was itching to Tube Roll.  I sent Email to Andy, but never received a reply.  I read about and watched the Upscale Audio site but never called to order anything.  My Amp Tech recommended some UOS (Used Old Stock) Sylvanias stamped as AMPEX on Ebay, so I bought them for $325 for (4).  Put them in and Amp sounded great.  Sadly it Red Plated on one tube, and had to go back to the Tech.  Now I am told the Tubes are VERY Used, and likely will return to the Groove Tubes.  I Called Andy at VTS, and had a delightful conversation.  I am considering a NOS set of Tung-Sols or GE Pre-Microwave Division (Per Andy) for about $800.  I also have ordered a set of British Military 6550 equivalents the 12E14 tubes for a song (Less than $200), as NOS.  I plant to have my tech review and install/bias them to optimal settings here soon.  I am hoping the 12E14s will really shine and might keep me from spending the big $$ for NOS GE/Tung-Sol. 

jeff in Detroit

[opnly bafld]

According to one tube data sheet I found the 12E14 should have pin 6 (beam plate) tied to pin 8 (cathode), these are connected internally on a 6550/KT88.

[FullRangeMan]

Sadly it Red Plated on one tube, and had to go back to the Tech.  Now I am told the Tubes are VERY Used, and likely will return to the Groove Tubes
Ebay is full of used tubes on the end of life, usually they are advertised as strong and can die at any moment.
It is not a good idea buy used tubes.

[Freo-1]

The GE6550A is my favorite 6550. 

[opnly bafld]

The GE6550A is my favorite 6550.

Sure why not, if you can find a matched set and can afford them if you do.