[BULK] - [Amps] NCL 2000?

[Dennis12Amplify at aol.com]

 Helge,

I have some Burle, (and RCA), 4662's that I had picked up at a Hamfest long 
ago from a guy I have bought at least a hundred ceramic tubes from over the 
past 25 years.

 I picked them up because I occasionally have to repair a National NCL2000 
and was told they were a 'plug in sub.' for the 8122. 

 The Burle have pink ceramic bases and the RCA's have white, but they all 
have the 4662 number on them and 'look' like 8122s.

 Can you tell me if that 'plug in sub.' rumor is true or not?

 I have not been able to find datasheets on either type so I have been 
reluctant to try the 'plug in' swap.

 As a result, they have just been collecting dust in my shop for 15 years or 
more.

Regards,

Dennis O.