[Johnson] 12AT7 Tubes

[jeremy-ca]

The European versions had better manufacturing tolerances that resulted in 
closely matching sections of that tube. Carefully matched US production will 
work well also.

We complain a lot about Chinese quality but our own quality was rather 
sloppy at times. How quickly people forget.

Carl
KM1H


----- Original Message ----- 
From: "David C. Hallam" <dhallam at rapidsys.com>
To: "Johnson List" <Johnson at mailman.qth.net>
Sent: Friday, May 30, 2008 10:00 AM
Subject: [Johnson] 12AT7 Tubes


> Is there any difference between a 12AT7 and an ECC-81?  I thought ECC-81 
> was
> just the European designation for a 12AT7.  However, in the Pacemaker
> Johnson calls for ECC-81 in the balanced modulator and 12AT7 in the phase
> inverter.  What's the difference if any?
>
> David
> KC2JD/4
>
>
> Johnson mailing list
> Home: http://mailman.qth.net/mailman/listinfo/johnson
> Help: http://mailman.qth.net/mmfaq.html
> Post: mailto:Johnson at mailman.qth.net
>