Date: Tue, 16 Feb 2010 00:38:05 -0500
From: Roger <sub1@rogerhalstead.com>
Subject: Re: [Amps] 4cx800a
>
4CX3000A filament 9.0VAC @ 41.5A = 373.5 Watts
4CX5000A filament 7.5VAC @ 75A = 562.5 Watts
Yah, but I hate to use more electricity to light the fire in the final
than for all the rest of my station. OTOH I have to admit those are
tubes that define rugged...Tubes with handles.
## I have to laugh at local QRP stations.. who all have 1500w base
board electric heaters at their feet. Why not kill 2 x birds with
one stone ?
7KV on the plate of a 4CX3000 @ 2A input gives 5.3 KW out
## it's actually 9500w. VE5FF built one..superb.
Man, now I know why the 4CX3000 and 3CX3000 are so popular.
## I'll tell you why. The 3CX-3000A7 is $50.00 more than a
8877, when I bought the pair of mine, has better imd, and will
make lunch meat out of 3 x 8877's . It's rebuildable, not a
throwaway, like oxide tubes.. + instant on. Even Ted Henry
agreed with me on that one.
OTOH it takes less to light the fires in the Triode versions, but more
drive.
### 7.5 V @ 50A = 375 w....so what? In actual practice, the fil
V is reduced to 6.7 V [ and less current] The bifilar is easy
to make.
## The 3CX-3000A7 is easy to drive. 50w in =1500w out.
Want more ? Use 150-200w of drive.. and melt 213-U
But, what the hay! Look at all the money you save by not needing
a socket although a 30 to 40# filament transformer is a lot of iron.
## The 3CX-3000A7 does use a socket. The fil xfmr is not an
issue, weighs 21 lbs. I mount mine external to RF deck,
on the next shelf down. 2 x flex 6 ga cables to RF deck,
small variac used to dial in the voltage.
## Now, the YC-156 is a great bargain..@ $200.00 The fil
requirements won't heat ur shack in winter.. or summer.
No socket, no parasitic suppressor required, and even far
easier to drive. Stick 100 w into one... and still melt 213-u
later... Jim VE7RF
73
Roger (K8RI)
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|