[SBE] Q 2 Cert exam - Loctal tubes

[k7cr]

You are correct on the Locktals...I did run across a few table radios
using them in the distant past...They were not AC/DC sets but rather
had power transformers etc.   I also recall (all too well) the Motorola
30D's that were full of them

Funny when old folks start looking back....Gee I'm one of them

Clay Freinwald



On Fri, Nov 16, 2007 at 8:57am Art Lebermann  wrote:

> The Loctal tube design was developed by Philco and Sylvania (in 1939),

in

> an effort to compete with new tubes from RCA.  This design eliminated

the

> Bakelite base, and used pins through a glass-button base.  The

"lock-in"

> design was necessary to keep the tube in the socket.  They were not

> designed specifically for auto radio use.  The "7" and "14" prefixes

were

> chosen to identify the tubes as Loctal types.  The "7" tubes had 6

volt

> filaments, and the "14" tubes had 12 volt filaments.  You'll find

specs

> in the early RCA receiving tube manuals. 

> Art Lebermann KGO / KSFO San Francisco 

> 

> 

> > [Original Message] From:  To:  Date:

> > 11/16/2007 6:57:54 AM Subject: Re: [SBE] Q 2 Cert exam 

> > As we know the Locktal was for automotive use, with 7 and 14 volt

> filaments.

> > 

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