[ARC5] 12SB7Y - where found?

[Kenneth G. Gordon]

On 3 Apr 2016 at 22:23, Phillip Carpenter wrote:

> Does anyone have one or two 12SB7 tubes? These are the same as 6SB7 except for
> the filament voltage. If so, please reply direct to me.
> 
> These were made by RCA for the military (I think it was an Air Force contract).
> They are still listed in stock by two military parts suppliers (though at
> extremely inflated prices...you know like the $900 hammer).

Really?!?!? I must admit to being very surprised since my checking every 
possible source for data on the 12SB7Y over the past year or two returned  
absolutely nothing.

AFAIK, there were never any 12SB7Y tubes built for normal users, but there 
most certainly could have been some made on special order for the military. 

Stranger things have happened.

I am very interested in where you have seen any 12SB7Ys for sale. I have 
never yet found any.

The 6SB7Y was specifically designed for use in early broadcast or home 
entertainment FM tuners and receivers and exhibits about double the 
conversion transconductance as the 6SA7 which it can directly replace.

Ken W7EKB