I also have a new Centaur (again, the "CQ" review - amazing the power of
these articles, huh?!). Since I don't have antennas up that will take
the power yet and no dummy load, I've only had it on the air for about
an hour at a friend's house for checkout. Only used it on 80m and 40m,
both CW (QSK) and SSB. My comments so far:
1. re - Thunk: This is inrush, and competitive amps don't appear to
have stepped power-on either. The MFJ/Ameritron 80B has inrush control,
but the price point is $1,200 (and 1KW output). What makes this
seem like more of a problem is that the cabinet top is acting like a
sounding board. Tap it once with your index finger - recognize the
sound? Yes, a stepped AC input voltage would be nice, but I don't know
enough about power supply design to debate whether it's necessary in
this amp or not. A little damping of the cabinet top would eliminate a
lot of the concern, I think.
2. Power meter measurements: on 80m and 40m, compared to a Bird peak
reading meter, the 411's meter read about 10% low. A conservative
reading and 10% off isn't too bad in my mind. Even if it were 10% lower
in power than the spec, this would be a fraction of a db at the RX end.
3. QSK - this was my main concern. Would it "play right" with my
IC-765. Answer: Yes - beautifully. No apparent change in keying
weight (though my Logikey could compensate if necessary). Ran a couple
QSO's at 25 wpm with no problem at all. A little light chatter from the
rig's and the amp's reed relays going, but not a problem.
4. Fan noise has been a concern of mine. It isn't quiet (is Doug DeMaw
going deaf?!). I've spoken to one big contester / DX'er around here and
his response was the same as TenTec's: having a little noise and
knowing the finals are safe is better than the alternative. Personally,
I use phones most of the time, but would still rather have a quieter fan
design (perhaps variable DC fan with temp sensing, etc.). In the
limited operating I've done with it so far, the airflow appears to be
more than adequate, but the noise is annoying.
5. Output power: No problem on 80m and 40m. I need to borrow a dummy
load before my 30 days is over to check this out on the rest of the
bands. Luckily my 765 has a tuner, so if the amp presents enough SWR to
drive the foldback limiter on the rig's output, I should be able to
overcome that.
6. Arcing: On the first transmission, there was a brief arcing sound
inside, couldn't tell from where, and it did not repeat again. Will
have to keep an eye on this.
This is my second attempt to append to a reflector, so hope it works. I
also hope the Centaur works, as it appears to work really well with my
rig. Would like to see a quieter cooling design.
73, Duane AC5AA
ac5aa@juno.com -or- duanec@prodigy.net
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