[Boatanchors] 6146B

[Glen Zook]

The earlier versions of the 6146 are less likely to
"take off" than the 6146B seires.  Also, if you look
at the design of the transmitters you will see that a
lot of them have the grid circuit more heavily
"loaded" which does require more drive but also
reduces the chances of the final "taking off".

When the neutralization circuits of the older
transmitters were designed they were very capable of
handling the characteristics of the 6146 and the 6146A
/ 8298.  However, since the 6146B is more likely to
"take off" this requires a different neutralization
circuit in many cases (i.e. Collins had to redsign the
S-Line neutralization circuitry to allow the use of
the 6146B).  This is not the fact that the components
used in the earlier transmitters are at fault, but the
fact that the 6146B is a completely different tube
from the earlier versions.

When the transmitters were designed that use the
earlier versions of the tube the 6146B was not even on
the drawing board.  The transmitters were designed to
work with the 6146 or 6146A / 8298 and did so very
well.  If there was a way of making the unit work
properly without neutralization then that was done
(makes tube replacement MUCH easier).  That was not
poor design, but very good design.  The fact that RCA
introduced the 6146B at a later date has no bearing on
the designs of equipment that were made before the
tube was introduced.

Glen, K9STH


--- fkamp at comcast.net wrote:

What was it about the older transmitters that allowed
them to get by without neutralizing the final.  Was it
something about the 6146A.  If so, what is it that
allows the 6146A to run without neutralization and why
would anyone want to do that and take a chance?
 
Un-neutralized finals are very poor designs and
unecessary when it is so easy to go with a decent,
neutralized design.
 
I dont understand why a 6146B could not be neutralized
or why the neutralization would not 'hold'.  Sounds
like those problems are the symptoms of a marginal or
inadequate amplifier design and maybe poor quality
compoments. Not the fault of the 6146B.
 
Maybe RCA unrealistically assumed that anyone involved
in amplifier design would have the sense to develop a
decent,  proper design.


Glen, K9STH

Web sites

http://home.comcast.net/~k9sth
http://home.comcast.net/~zcomco

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