[Heathkit] DX-100B on Phone - bad audio distortion / oscillation

Rick Poole wa1rkt at arrl.net
Thu Dec 1 23:43:38 EST 2011


At 09:44 PM 12/1/2011, Glen Zook wrote:

 >>>>>
>What tubes are you running in the final?  Many DX-100 series 
>transmitters definitely do NOT like 6146B/8298A tubes  If you are 
>running 6146B/8298A then try plain" 6146, 6146A/8298, or 6293.  You 
>can mix a 6146 with a 6146A/8298.  But, mixing a 6146 or 6146A/8298 
>with a 6146B/8298A is just asking for trouble.
<<<<<

Good evening, Glen.

Good call.  They are 6146B's.  I knew about some issues with -B's 
from my experiences with my Collins KWM-2A which doesn't like the 
-B's either.  Oddly enough, though, the Collins seems perfectly happy 
with -W's.

I have a matched pair of -W's (spares for the Collins) so I tried 
them in the DX-100... no joy, same problem.

So, where's the best place to get 6146's or -A's?  RF Parts only 
carries -B's and -W's, at least that's all that's on their 
website.  There are the usual suspects on ebay that I never heard of, 
have no idea what I'll be getting, and in one case wants $75 for a 
pair and they're not even new or NOS.  Google yields Tube Depot and 
The Tube Store, neither of which I've ever heard of but at least 
their prices seem more reasonable, $19 and $24 each.

Speaking of matched pairs, should I go for a matched set or just pick 
two at random and go for it?

If I do get the 6146's or -A's, should I remove the neutralizing wand 
or just leave it in?



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