6146 Replacement

[Glen Zook]

The 6146B / 8298A is NOT the same tube as the 6146 and
6146A / 8298.  RCA originally said that the 6146B /
8298A was completely compatible with the earlier
versions.  Unfortunately, this did not prove to be so.

Many of the transmitters that were designed for the
earlier versions of the 6146 are definitely NOT
"happy" with the 6146B.  Often the 6146B / 8298A will
not neutralize in transmitters designed for the
earlier versions.

Now I have worked on various transmitters of exactly
the same model with serial number of within 10 of each
other in which the 6146B / 8298A worked fine in one of
them and in the others there were all sorts of
problems.  Therefore, I never say that the 6146B /
8298A will never work.  However, I definitely
recommend caution when substituting the 6146B / 8298A
for the earlier versions.

If the final will not neutralize then immediately
replace the 6146B / 8298A with an earier version.  If
the neutralization does not "hold" (the neutralization
varies) then replace the 6146B / 8298A with an earier
version.  You need to watch the neutralization for
several days to see if it "holds".

When a 6146B / 8298A tube is used in place of the
earlier versions often the stage "takes off" putting
out spurious emissions and parasitics.  This can
result in the self-destruction of the tube.

Again, the article on the 6146 family of tubes can be
found at

http://k9sth.com/Page_2.html

and is the first link under the "Articles" heading.

Now there are people who say that they have never had
any problems at all replacing the earlier versions
with the 6146B / 8298A and I believe them.  But, in
the vast majority of cases replacing the earlier
versions with the 6146B / 8298A causes problems.

Also, NEVER mix a "B" with earlier versions.  This
will really cause problems.

Glen, K9STH


--- Gregg <gwyz at USA.NET> wrote:

The correct substitute would be the 6146B.









Glen, K9STH

Website:  http://k9sth.com

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