[Boatanchors] Heathkit TT-1A Restoration Article - Electric Radio

[Gary H. Harmon, Jr.]

I'm not a tube tester expert but a quick review of the TT-1 manual shows the
mention of "mutual conductance" in numerous areas.  Page 6 says, "Of the
many measureable characteristics of vacuum tubes, mutual conductance is the
one most closely associated with actual operating performance.  This is the
method used for testing amplifier tubes in the HEATHKIT model TT-1."  "The
term 'proportional mutual conductance' is derived from the fact that
proportional values of element voltages are applied to the tube under test."

What am I missing?

Gary H. Harmon, Jr. - K5JWK
6003 Archwood
San Antonio, TX 78239-1504
210.657.1549h / 210.884.6926c

"Too many projects, not enough time".



-----Original Message-----
From: Geoff [mailto:geoffrey at jeremy.mv.com] 
Sent: Saturday, June 23, 2012 8:55 AM
To: Gary H. Harmon, Jr.; BOATANCHORS2 LIST
Subject: Re: [Boatanchors] Heathkit TT-1A Restoration Article - Electric
Radio

While the article was a good read I believe the claim that it is a mutual
conductance tester is in error. Hickok held the patents on those and the
TT-1, some Jacksons, Eico 666, and a few others are "Dynamic Conductance" 
testers which simply means an AC signal is applied to the grid of the tube
under test.

I ran extensive tests between my restored/calibrated Hickok 752A (still has
the National Radio ID tag) and a Jackson 648S and they track very well over
a wide range of tube types.
An I-177 and TV-7C complete the active testers here with a few other shelf
queens or parts units.

Carl
KM1H


----- Original Message -----
From: "Gary H. Harmon, Jr." <gharmon at idworld.net>
To: "BOATANCHORS2 LIST" <boatanchors at mailman.qth.net>
Sent: Friday, June 22, 2012 10:25 PM
Subject: [Boatanchors] Heathkit TT-1A Restoration Article - Electric Radio


>A good friend of mine, Ron/AB5WG, wrote a great article on his electrical
> and cosmetic restoration of a Heathkit TT-1A tube tester which appeared in
> the latest issue.  Not only does it result in a beautiful specimen, the
> article goes into detail on the types of testers and the amazing
> capabilities of the TT-1A.
>
>
>
> Electric Radio (ER) has given me permission to share the article.  If you
> want a copy, let me know.
>
>
>
> Finally, ER is a wonderful magazine for those of us who appreciate the old
> stuff.  If you don't subscribe, you should consider a subscription.
>
>
>
> Vr,
>
>
>
> Gary H. Harmon, Jr. - K5JWK
>
> 6003 Archwood
>
> San Antonio, TX 78239-1504
>
> 210.657.1549h / 210.884.6926c
>
>
>
> "Too many projects, not enough time".
>
>
>
>
>
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