In article , Alun
writes:

You might be right about needing a 100W rig to drive most linears, but not
about the 6146s.

Check the ratings. You'll find that I'm right. Sorry, Alun, but I checked my
info before posting and it's accurate.

A pair of 6146 tubes will deliver 280W upto 30 MHz and
half that upto 60MHz acoording to the spec.

The 6146 is rugged, but not that rugged.

The maximum rated power output of a pair of 6146s in Class AB2 *audio* service
is 131 watts. Typical Class AB1 RF service will deliver less.

6146Bs can deliver a bit more. But even at maximum ratings, a pair of 6146Bs is
only rated at 240 watts *input* (Class C).

The old Yaesu FTDX-560 was
rated at 280W out with a pair off 6146s (560W input power, hence the model
number).

560 W input is more than three times the maximum rated input power for 6146s
and more than twice the rated input power for 6146Bs.

The FTDX-560/570 (570 was a deluxe model rated 10 W more) and the earlier
FTDX400 did not use 6146s or any member of the 6146 family.

Those old Yaesus all used 6KD6 sweep tubes, as did the FL-2000 amplifier. (The
FL-2000 was based on a QST article of about 1968 in which up to six 6KD6s were
used in a low-cost amplifier).

But don't take my word for it. NJ7P has a neat tube database, and there are web
pages devoted to early Yaesus.


73 de Jim, N2EY