6146 / 6883

[Glen Zook]

In the Heath SB-Line transceivers (SB-100, SB-101,
SB-102, SB-110), and other manufacturers transceivers
as well, the heater ("filament") voltage is actually
12.6 volts.  Therefore, the heater connections of the
final amplifier 6146 tubes are wired in series.  You
connect these heaters in parallel and substitute the
6883 series (6883 / 6883A / 8032) tubes which have
been used in commercial FM units for years and are
available quite often for much less than the 6146 /
6146A / 8298 tubes.  It only requires the moving of
one wire and the grounding of one pin on the tube
socket.  If you want to return the the original
configuration, it only takes a few minutes.

The 12 volt 6146 equivalent tubes often go "wanting"
at hamfests, etc. because most of the amateur
equipment uses the 6 volt versions.  Thus, you can get
several of the 12 volt equivalents for less than one
of the 6 volt versions.

I have done this in my SB-110A, and an SB-102, and it
works fine.  The SB-400 and SB-401 have the 6146 tube
heaters wired in parallel so you cannot do this.  What
you have to do is to look at the schematic and see if
the 6146 heaters are in parallel or series.  If in
parallel, then you have to leave them alone.  However,
if in series, then you can rewire and use the 12 volt
equivalents.

For more information on the 6146 series of tubes, you
can go to either of my websites for the text of the
article that I wrote for Electric Radio on this
subject.

http://home.attbi.com/~k9sth

http://home.attbi.com/~zcomco

Glen, K9STH



=====
Glen, K9STH

Web sites

http://home.attbi.com/~k9sth
http://home.attbi.com/~zcomco

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