[Amps] Power from Pair of Eimac 4 x 150 a / 7034?

[Carl]

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 at telus.net>
To: <amps at 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 at kd4e.com" <qrv at kd4e.com>
> To: "amps at contesting.com" <amps at 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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