[Drake] 6JB6A tubes

[Garey Barrell]

Marty -

I think the answer to this is that most of the tube  _manufacturers_  
supplied tubes to others, (and often each other,) for them to "brand" 
however they liked.  They would sell internal assemblies or even 
finished tubes to each other in the interest of availability.  Say 
Raytheon made 6JB6s, but their line was set up to make 5U4s and their 
distributors were ordering 6JB6s.  Raytheon would purchase a lot from 
someone who either had an overstock of 6JB6s, or was at least set up to 
manufacture them, and put their brand on them and put them in Raytheon 
boxes for sale as "Raytheon" tubes.

Obviously Zenith didn't  _make_  tubes, but purchased them from a tube 
manufacturer, put the Zenith brand on them and then put them in Zenith 
boxes, or new TVs, or sold them to Zenith TV owners as replacements.   
Most consumer equipment of the time had labels urging the owner to 
replace tubes "ONLY with Genuine Zenith (or whatever) tubes".   
Hallicrafter's receivers came with "Genuine Hallicrafter's tubes" in them.

So perhaps it's more correct to say that in over 40 years of owning, 
using and servicing Drake transmitters, I have never had a Sylvania, RCA 
(Drake's choices, in order, at manufacture), Zenith or GE 6JB6 that did  
_NOT_  neutralize and work as expected.  On the other hand, I  _HAVE_  
had difficulties with more than one sample of International, Raytheon, 
Standard and Westinghouse branded 6JB6s.   Close examination of the ones 
that I have had problems with had internal structures that did not 
"match" the structure of the brands that DID work.  The "generic" 
replacement brands, International and Standard, were sold primarily 
after all or most of the US manufacturers had ceased production, so I 
don't know where they were made.  I also have no idea of the 
qualifications and skills of the companies that made them.

So maybe over the years Raytheon bought 6JB6s from various manufacturers 
and I was just unlucky enough to get the ones that were made by the 
"wrong" guys, and the ones you got were made by RCA??  It would be 
interesting to compare the internal structure of the ones you have that 
work against a Sylvania or RCA branded tube.

73, Garey - K4OAH
Atlanta

Drake C-Line Service Manual
<http://www.k4oah.com>


Allen (Marty) Martin wrote:

>Interesting thread. I have had good luck with the Raytheon tubes! Apparently
>others have not though.
>
>Marty
>
>----- Original Message ----- 
>From: "fkamp" <fkamp at comcast.net>
>To: <k4oah at mindspring.com>
>Cc: "Drake list" <drake at mailman.qth.net>
>Sent: Wednesday, February 15, 2006 9:45 AM
>Subject: Re: [Drake] 6JB6A tubes
>
>
>  
>
>>Garey Barrell wrote:
>>    
>>
>>>Darrell -
>>>
>>>Interesting...  The International tubes I tried would neutralize with
>>>no problem, but were very hard to drive, particularly on 15 and 10M.
>>>I attributed it to the considerably different internal lead structure
>>>compared to US made tubes.
>>>
>>>Some brands require considerably different neutralization
>>>capacitances.  I'd just as soon avoid making changes to the
>>>transmitter though until it becomes necessary.  So far "good" brand
>>>tubes are still readily available.
>>>      
>>>
>>Before I converted my Drakes to use 6146s, I used Sylvania brand 6JB6s
>>with no problems at all.
>>
>>Regards,
>>Frank Kamp
>>K5DKZ
>>    
>>