Re: new tubes

to: Ben

One reason tubes run red hot plates is due to parasitic oscillations ---
very high freq oscillations that don't help the fundamental at all.  The
older tube editions of ARRL's Radio Amateur's Handbook have some good
articles on dealing with these problems.  Also, be sure to run fil.aiment
chokes as well.  Many tube experimenters ignore these two areas and their
plates do run hotter than they should.


> From: Tesla List <tesla-at-pupman-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: new tubes
> Date: Thursday, December 03, 1998 4:59 PM
> Original Poster: "Benjamin W. Bouxsein" <bbouxse-at-comp.uark.edu> 
> Just went to old radio dude place today, and picked up a pair of 803's
> a pair of 866A's.  Also he gave me a gigantic transmitter coil form.  The
> thing is at least 6" diam.  and 12" tall. Even has a primary form with
> ceramic insulators.  May make a nice form for the tube coil I am
> My question is: He mentioned seeing 803's in a push-pull circuit being
> at 2000W, but I only show the max plate disipation as 125W.  He says its
> possible, but they glow red hot.
> Comments?
> Ben Bouxsein