[Amps] HB amps

[W.F van Wyk]

Hello fellow enthusiasts,

I must give support here and echo the sentiment of construction and if that
entails using 813's so let it be the case.

I have built a few amps getting experience using 813's and they are more
than capable of running the legal 400 watts PEP allowed in South Africa. So
they are not that happy on 10 meters, that becomes a technical discussion
nothing more.

I have had much more interesting discussion on the DX bands when I mentioned
my homebrew 813 amps than when I mentioned I switched the ALPHA on.

Like it was said, "Power to the Home Constructor" ... "long live the 813 and
other vintage valves"


73

Wynand

ZS6ARF

-----Original Message-----
From: amps-bounces at contesting.com [mailto:amps-bounces at contesting.com] On
Behalf Of Ed Swynar
Sent: 05 March 2006 03:33 PM
To: Ian White GM3SEK; amps at contesting.com
Subject: Re: [Amps] HB amps

Hi Guys,

No matter the IMD characteristics one db. either way, I'm of the opinion
that if somebody wants to uphold the noble Amateur Radio tradition of our
group being a collection of "...tinkerers & experimenters" by actually
BUILDING something, he/she should be applauded...!

Most anyone with a VISA card nowadays can buy the most advanced of
appliances, but that holds little sway in my opinion as to who the TRUE Ham
Radio op is...

Heck, I've built self-excited 1929-style Hartley & Colpitts transmitters,
and have actually USED them on the air, all-the-while sitting alongside my
imported rigs from Japan, Inc. --- and nobody needs to present me with the
argument of which rig is superior to the other, Hi. I already know, it's
quite obvious, but re. the old technology / hardware, I actually BUILT
something, as opposed to having simply UNBOXED it...

"...813 lovers, wherever you may be, go forth and prosper, indeed, go forth
and MULTIPLY...!"

~73~ Eddy VE3CUI - VE3XZ


----- Original Message -----
From: "Ian White GM3SEK" <gm3sek at ifwtech.co.uk>
To: <amps at contesting.com>
Sent: Friday, March 03, 2006 2:44 PM
Subject: Re: [Amps] HB amps


> Gary Schafer wrote:
> >>
> >> An 813 only has 125W dissipation, so by today's standards they are
small
> >> tubes. You'd need four to equal a single 3-500Z, which will glow just
as
> >> nicely.
> >>
> >> A pair would be struggling to reach even the "1kW input class", and the
> >> clean linear output is unlikely to be more than 400W. Even if you have
a
> >> box full of 813s, is it worth the effort of building such a small amp?
> >>
> >>
> >>
> >> --
> >> 73 from Ian GM3SEK
> >
> >A pair of 813's will easily produce 600 watts output and do it for years
and
> >years. They are very rugged tubes. I have an amp with a pair of them that
I
> >built in the mid 60's and it still has the same pair of tubes. At one
time I
> >ran them with over 3000 volts on the plates for several years with the
> >plates regularly showing color and power out well above 600 watts.
> >The same tubes now run at around 2500 volts and still put out 600 watts
and
> >no color.
> >
> >Not the best tube in the world but for the price and as rugged as they
are
> >they are hard to beat.
> >They will perform well on a wide range of voltages too. 2000 to 3000
volts.
> >
>
> I don't dispute the raw output figures, or the ruggedness either; but
> you didn't address my point about "clean, linear output". How do the IMD
> levels at 600W output compare with a 3-500Z?
>
>
> --
> 73 from Ian GM3SEK
>
> _______________________________________________
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>


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