[Boatanchors] Heathkit TT-1A Restoration Article - ElectricRadio

[Geoff]

As Ive already stated Hickok had the patent on the mutual conductance 
circuit as I understand it. What Heaths marketing folks and manual writers 
did would have aggraved Hickok if it indeed violated the patent.

Scroll down to Dynamic Conductance Tester
http://en.wikipedia.org/wiki/Tube_tester

If you know different Id like to hear it.

Carl
KM1H





----- Original Message ----- 
From: "Gary H. Harmon, Jr." <gharmon at idworld.net>
To: "'Geoff'" <geoffrey at jeremy.mv.com>; "'BOATANCHORS2 LIST'" 
<boatanchors at mailman.qth.net>
Sent: Saturday, June 23, 2012 9:44 PM
Subject: Re: [Boatanchors] Heathkit TT-1A Restoration Article - 
ElectricRadio


> 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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