[Johnson] Tube Designation

[Langston, Mike]

Last time I tuned a Pacemaker was 1978. I was feeding a T-bolt and
remember that I couldn't depend on the Pacemaker meter for accurate
carrier null. I had an output meter downstream of the T-bolt and nulled
for minimum reading on the output meter. I don't remember what tubes
were in it.

Mike KL7CD

-----Original Message-----
From: johnson-bounces at mailman.qth.net
[mailto:johnson-bounces at mailman.qth.net] On Behalf Of Peter Markavage
Sent: Tuesday, April 22, 2008 12:48 PM
To: Johnson at mailman.qth.net
Subject: Re: [Johnson] Tube Designation

I seem to remember when I had the 12AT7's in the Heath SB-10, I had to
constantly ride the carrier null pots with each transmission. Replacing
the tubes with 6201's and replacing the null pots with 10 turn devices
cured that problem along with the improved carrier suppression.

Pete, wa2cwa
http://www.manualman.com

On Tue, 22 Apr 2008 13:21:19 -0400 "David C. Hallam"
<dhallam at rapidsys.com> writes:
> Pete,
> 
> I can't seem anything one way or the other.  Right now the Pacemaker 
> is a
> work in progress.  When I am finished refurbishing maybe I will run 
> some
> tests.  I can try a 12AT7, ECC-81, 6201, and any other MilSpec 
> variants I
> can get my hands on and look the carrier and side band suppression 
> on my
> spectrum analyzer.
> 
> David
> KC2JD/4
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