[ARC5] 12SB7Y - where found?

[Phillip Carpenter]

Ken and Others,

I found out the story on the 12SB7 from Jim Cross at Vacuum Tubes, Inc.

Jim says that only a few engineering samples were ever made and these were only made by Ken-Rad. He has one sample in his collection.

Jim said that LEEDS never had those they listed and Lintech's listing of a RCA 12SB7 is phantom stock.

So only a few were ever made and none for production.

Respectfully,

Phillip W4RTX 

Sent from my iPhone

>> On Apr 4, 2016, at 11:50 AM, Kenneth G. Gordon <kgordon2006 at frontier.com> wrote:
>> 
>> 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