[Heath] [Heathkit] 6146B Issues

[Glen Zook]

The DX-35, DX-40, and the DX-60 series "load down" the grid circuit.  This, in turn, requires considerably higher output from the driver stage.  As such, Heath did not neutralize those transmitters.  With the "loaded down" grid, the 6146 in the final amplifier is much less likely to "take off" and neutralization is not usually required.  In most cases, the 6146B/8298A or 6146W tubes will work fine.

Of course, there are always exceptions.  As such, I will not say that the later tubes will work in every DX-35, DX-40, and DX-60 series.  However, there is a very good chance that the tubes will work fine.
 
Glen, K9STH


Website:  http://k9sth.com



On Saturday, October 12, 2013 10:48 AM, RAY FRIESS <rayfrijr at msn.com> wrote:
 
Glen ...   question.
Does this apply as well to the simple Heathkits like the DX 40 and DX 
60?    I don't recall off hand that those simple ones require or even 
have provision for neutralizing.

Ray  wa7itz



________________________________




Date: Fri, 11 Oct 2013 18:46:40 -0700
From: gzook at yahoo.com
To: gharmon at idworld.net; heath at puck.nether.net; heathkit at mailman.qth.net; heathkit at yahoogroups.com
Subject: Re: [Heath] [Heathkit] 6146B Issues


There is no list.  However, the 6146B/8298A and the 6146W tubes require different neutralization and most of the Heath SB-Line equipment are very "iffy" in whether or not they can neutralize.  Some units seem to work OK but even more have problems.  One can modify the neutralization circuit so that the transmitters / transceivers will neutralize.  However, for "plug and play", one really needs to use the 6146, 6146A/8298, or 6293 tubes, especially if they have problems neutralizing the tubes.

There are those who violently disagree with my article on the 6146 family of tubes:

http://k9sth.com/uploads/The_6146_Family_of_Tubes_1.pdf


However, over the years, I have literally seen well over 10,000 transmitters that use the various 6146 family of tubes and my observations are outlined in the article.

There are those who say that they have used the 6146B/8298A or 6146W in transmitters that were designed for the 6146 or 6146A/8298 without any problems.  I do believe them.  However, I have received notice from a LOT more people who say that they have had problems and went back to the earlier tubes.  It seems to be how the individual tolerances of the components "add up" as to whether or not the later tubes work.

I have worked on individual transmitters, of exactly the same model, with serial numbers within 10 of each other.  With those transmitters 1 was happy with the 6146B/8298A and the other 2 were very unhappy.
 
Glen, K9STH


Website:  http://k9sth.com



On Friday, October 11, 2013 5:13 PM, "Gary H. Harmon, Jr." <gharmon at idworld.net> wrote:
 
I seem to remember there are some pieces of Heathkit that are not
HAPPY-HAPPY-HAPPY with 6146B tubes.  Is this a myth or is there a list of
pieces that prefer to not see a 6146B?



Thanks and 73,  



Gary H. Harmon, Jr. - K5JWK

6003 Archwood

San Antonio, TX 78239-1504

210.657.1549h / 210.884.6926c/t



"Retirement means every day is a Saturday except Sunday"

http://www.grissomroadcoc.org





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