Date: Mon, 28 Mar 2011 14:38:12 -0500
From: "Diane & Edward Swynar" <deswynar@xplornet.ca>
Subject: Re: [Amps] Homebrew is back..
Hi Roger et al,
I use a pair of 813s in parallel grounded-grid service here in my homebrewed
KW amplifier, and---I'm blushing as I type this!---but I have NEVER EVER
purchased any of the jugs that are in it, or the spares that I have here,
brand new...
They are all either Hamfest finds, or freebies from friends.
Life's far too short to pay-off a retiree's ransom for new & exotic
tubes---and I have yet to hear anyone at the DX end of my QSOs asking me (or
expressing any care whatsoever) which tube(s) I might be using! Hi Hi
~73~ de Eddy VE3CUI - VE3XZ
&&& 813`s are a half decent tube....but not in the same league as a YC-156,
YU-148
or 3CX-3000A7 A single YC-156 = 14 x 813`s A YU-148 = 20 x 813`s.....and
yes,
the the DX station will hear the difference. The IMD on the 813 and 4-1000
is nothing to write home
about...and ditto with russian tetrodes. The folks with the infamous 4CX-1600B
in their Ten tec`s are
really screwed. Apparently, it can be converted to another tetrode. IMO, I`d
convert it to a
chinese 8877....and be done with it.
Jim VE7RF
**********************************************
----- Original Message -----
From: "Roger (sub1)" <sub1@rogerhalstead.com>
To: <amps@contesting.com>
Sent: Monday, March 28, 2011 1:11 PM
Subject: Re: [Amps] Homebrew is back..
> On 3/28/2011 12:02 PM, Lou Spradling wrote:
> > It has been several years since I have attempted to "build something",;
and in
> > that frame I become an (operator). A real pleasure to pursue the hobby
with
> > researching material for 10-160 linear amps ! and in doing so I
discovered this
> > reflector !! Wow, a real goldmine of experienced builders in my
library'. It's
> > great.
> >
> > Now, my problem is trying to locate one or more Tubes 4CX1600b for a
Ten-Tec
> > Titan II, OR. any thoughts or suggestions as how I should approach this
item. It
> > is working fine but it looks like a little rework of the final area
will be
> > required if I can locate a tube that I should use.?
>
> There are people on here who know a lot more about tubes than I, but:
>
> Unfortunately even though "The Handbook" still shows projects using it,
> the only 4CX1600B's left are the ones "a few" might have on their shelf
> for spares, or "that planned project". IOW they are no longer in
production.
>
> If you still desire a tetrode of that size or close to it, there are the
> 4CX1500Bs, 4CX1000s, Chinese FU728Fs in production. There are lots of
> surplus NOS Russian Triodes and Tetrodes available with plate
> dissipation ratings from around 800 watts to 4000. but the price on the
> good ones is going up, but still cheaper than new 8877s or 4CX1600Bs
> when they were available. Calling them good will probably raise Carl's
> blood pressure <:-))
>
> The field for legal limit triodes, if you want a tube still in
> production. 8877s, 3CX and 3CPX800s as a pair, are popular, but pricey
> and available as tested pulls much more economically. Although no
> longer made the 3CX1000A7s are still found occasionally.
>
> The more popular tubes on here are the substantially larger 3CX3000A7
> and 4CX3000A7 (ungodly pricey socket but available used) and the YC156
> (tube with handles and no socket required) is probably the most popular.
> Any of these can easily be set up to run the legal limit plus a bit, but
> we are talking tubes that weight from around 6# to nearly 10# and about
> 10" tall with about 5" diameters.
>
> 73
>
> Roger (K8RI)
>
>
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