He is asking about a PAIR of tubes in an amp he is looking at.
One option there is that other tubes in the 4X150/250 family can be used
that offer much better IMD
For many a $700 Chinese 8877 is not an option.
Carl
KM1H
----- Original Message -----
From: "Jim Thomson" <jim.thom@telus.net>
To: <amps@contesting.com>
Sent: Saturday, December 27, 2014 11:52 PM
Subject: [Amps] Power from Pair of Eimac 4 x 150 a / 7034?
Date: Sat, 27 Dec 2014 13:34:58 -0500
From: "qrv@kd4e.com" <qrv@kd4e.com>
To: "amps@contesting.com" <amps@contesting.com>
Subject: [Amps] Power from Pair of Eimac 4 x 150 a / 7034?
What is the probable output of an amp using
a pair of Eimac 4 x 150 a / 7034 tubes on 6M?
*David*
~KD4E~
Nevils, Georgia USA
## 1000-1200w pep out on 6m. But why mess with a FOUR tube
amp for 6m..or any other band ? Then toss in the regulated
screen supply etc. Then you will also require FOUR sockets,
FOUR chimneys, FOUR anode connectors etc, etc, etc.
Then try and figure out why the plate current doesn’t divide equally
amongst the FOUR tubes. Then when one of the FOUR tubes goes screwy
on you, and the amp gives you grief, then you gotta figure out which of
the
FOUR tubes it is. If you do embark on this project, you have to make
sure
you have FOUR known good, full output tubes....and plenty of good spare
tubes.
## IMO, this is a classic case of where a single 8877 would kill about 6
birds
with one stone. A new chinese 8877 would do the trick, dead simple, no
screen supply
to mess with, superb imd, and an easy 2kw output... + 1500w CCS anode
diss. Only
1 socket/chimney / anode connector required. Easy to trbl shoot, it
either works, or it doesn’t.
The 8877 will last one helluva long time, if you look after it with the
appropriate grid
over current protection, high swr protection etc.
## what appears to be a low cost 6m amp, with surplus 4X-150A tubes will
turn out to be
tedious process in the end. Why complicate it ?
Jim VE7RF
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