COLIN LAMB wrote in message
. net...
There may be more to it than that. The advantage of sweep tubes was that
they worked very well at lower voltage. For the same power level, the
6146
required more voltage. Also remember this was before the 6146B arrived.

I am not a collector of Drake equipment (and I am not a fan of sweep
tubes),
but didn't the TR-3 arrive first? Three tubes were used for a lot of
power.
The use of the sweep tubes there may have set the foundation for later
transmitters and transceivers.

I remember a conversation with a friend some 45 years ago. He was
lamenting
that the Hallicrafters HT-32 used the 6146, because it was so wimpy and
actually had lower plate dissipation than the 807 it was supposed to
replace. He returned the HT-32 and bought an old Harvey Wells Bandmaster.
Then worked the world on 10 meters with that rig.

73, Colin K7FM

Fine Colin... but some of us used the HP-23 Heathkit power supply for the
Drake tranceivers---Heathkit used the 6146 for virtually all of their
transmitters and tranceivers. I myself used the HP-23 for powering my TR-3
with no problems; of course, the jack had to be changed and re-wired. The
HP-23 delivered 700 volts under load---admittedly a bit higher than what
Drake wanted for their sweep tubes; 650 volts.

I think the 6146 pre-dates the Drake rigs. I believe the 6146 came out in
the early 1950's along with the 5763 which supposed to be it's driver (Drake
used the 12BY7A as a driver). I remember the RCA ads for those tubes on the
back of QST.

RG