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[Amps] Homebrew is back..

To: <amps@contesting.com>
Subject: [Amps] Homebrew is back..
From: "Jim Thomson" <jim.thom@telus.net>
Date: Tue, 29 Mar 2011 04:17:44 -0700
List-post: <amps@contesting.com">mailto:amps@contesting.com>
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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