[AMPS] What (modern) tube to use?

[km1h@juno.com]

On Thu, 18 Feb 1999 15:54:11 -0500 "Joe Subich, W8IK/4" <W8IK@ibm.net>
writes:
>
>
>The recent "amps" discussion of which tube to use for building a new 
>CW
>amplifier started me thinking ...
>
>If one were building a new amplifier (or buying one of the new 
>commercial
>units) what tube or tubes in the case of a pair would one use?  
>Criteria
>are reliability at 1500 watts output, tube cost, availability of 
>replacement
>tubes if needed in the future and overall relability of the amplifier. 
> The
>100 Amp filaments rule out a "super power" solution like the 
>4CX5000/8170 or
>4CX10000/8171 and the 4-1000/8166 seems to be usable only for a 
>homebrew
>solution (and then, only if one has a junk box full of them or access 
>to
>an old AM station <G>).  The present options seem to come down to: (1) 
>a
>pair of 3-500Z,  (2) a pair of 3CX800, (3) 3CX1200A7, (3) 
>8877/YU-158,
>(4) a pair of 4CX800/GU-47b, or (5) 4CX1600.
>
>Whether one builds an amplifier or purchases a commercial box, the 
>same
>general concerns apply.  A good builder will pay attention to overall
>circuit design (band switch, pi/pi-L losses, cooling, control 
>circuits,
>stability, etc.) and someone buying a commercial amplifier should 
>consider
>the same factors.
>
>73,
>   ... Joe Subich, W8IK/4  ex-AD8I
>       <W8IK@IBM.NET>

For an indestructible amp at 1500W out and 100W drive do not overlook the
3CX3000A7 or the 3CPX5000A7/YC-156. 
Yes the former really likes its 380W filament but it is almost instant
on. But a good version of either should last a lifetime.

Either tube is virtually idiot proof which can be a big plus in a no
frills home brew amp.

73  Carl  KM1H


.




>
>
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