Hi Bob,
Thank you for your sane reply affirming exactly what I have been doing in my
use of the 4-250A. I always take what is presented on this site and do my
best to eliminate the technical extreme as well as the non-technical
content. Somewhere in between that is the technical education I seek. I must
admit as a non technical amp builder (I am a political scientist by career)
I have learned a lot from the likes of Rich, Ian and lately again Tom).
My conclusion and position I am going to take here in ZS is that the 4-250A
can be "pushed" to levels above 800 watts basically by increasing the plate
voltage and the class of application but at the expense of reliability, IMD,
linearity and most likely the wrath of the neighborhood. So technically one
should agree the higher RF levels can be obtained but in the practical
application in our hobby should be frowned on and discouraged.
-----Original Message-----
From: robert briggs [mailto:vk3zl@bigpond.com]
Sent: 02 July 2006 03:08 AM
To: zs6arf@telkomsa.net
Subject: 4-250A
Hi Wynand,
Oh Boy.don't we get a lot of technical garbage on the Amps site.I have
been running
a pair of 3.5-750A European version of the Eimac 4-250A for years on 160
meters.
To all practical purposes I have never seen more than 7-800watts output
from them.I generally run 3kv on them in the cw mode and to date I am
still using the original tubes in the amplifier.I can never understand
why anybody wants to push good tubes way past their limit.
Check http://vk3zl.gs35b.com amplifier site for my latest amplifier.
Kind Regards....Bob VK3ZL..
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