But it seems that 833A/GU48 are not good above 40m band. And it seems that are
unstable as well.
So, looks like 4 x GU81 grounded grid, used as triodes, are the best deal, in
monoband design for 20m band.
Needs more input but for me is fine since my radio gives 200w and I have one
more amp if needed.
Now I need some schema to follow, and levels to use.
Thank you anyway.
73, Maximo - EA1DDO
> Date: Tue, 28 Feb 2012 10:31:33 -0500
> From: email@example.com
> To: firstname.lastname@example.org
> Subject: Re: [Amps] 4 x Glass Glowing tubes
> Máximo EA1DDO_HK1H wrote:
> > Hi all, Bill,
> > Yes, Bill is right.
> > I am not looking for just watts. I donÂ´t want a closed box with ceramic
> > tubes inside (I already own one).
> > What I would like to get is a beauty looking amp with good/high quality
> > audio, based on glass tubes.
> > Let me change the question.
> > What tubes do you recommend to me to build a 14 MHz monoband amp from
> > these; GU48/833A, GU81M or GU5B?
> > GU5b (triode) is powerful, cheap and AB2 class quality, the only issue is
> > the blower/noise they need. http://tubedata.tubes.se/sheets/018/g/GU5B.pdf
> > GU81M, tetrode, are cheap, and I guess has quality as well, no blower (or
> > small one), but tetrode needs more power supplies
> > http://tubedata.tubes.se/sheets/018/g/GU81M.pdf
> > GU48/833A, (triode), are cheap, B class, unstable?
> > http://tubedata.tubes.se/sheets/018/g/GU48.pdf
> > It could be just monoband amp, for 14 MHz, may be I can add 7 MHz later on.
> > Thinking in 4 tubes to get blowing glass enough and power between 4 to 10
> > Kw).
> > Any other glass tube?
> > Any recommendation?
> I wasn't asked, but I would vote on the four GU48/833A, (triode) with
> push-pull paralleled pairs.
> A muffin fan is all that you need to get the heat out of the box.
> 73 Ron KA4INM - All E-mail sent to this address shall linger in the
> Google cloud forever!
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