[TenTec] Centaur quiet fan?

[John Clifford]

There are plenty of computer system cooling fans available that run on 12VDC
that have a thermistor so that fan speed (and noise) varies with the
temperature (the fan's speed is proportional to the air temperature).  I
have a Centaur and can see from the high-level wiring diagram that there is
14VDC available inside... could this be tapped and used for a replacement DC
fan that draws 200 mA or under?

Although my station is off, I just turned on my Centaur to get a reminder of
how loud the fan is.  It is MUCH louder than the four computers I have
running in the shack (drowns them out).  It's got to be 65 to 70 dB.

I've read that Ten-Tec over-spec'd the fan to ensure that the 811As would
have a long life, since running the amp at a full 600w is really pushing
them.  I've also read that switching to 572Bs (or running at less than full
power with the 811As) would allow the tubes to run cooler, thus allowing for
a quieter fan without endangering tube life.  I'd welcome any comments from
other, more knowledgeable Centaur owners.

BTW, I picked one up about a year ago because I wanted an amp and after
comparing the Centaur to the Ameritron AL811, it offered QSK, could be
bought in as-new condition for less than a new AL811, and it was a Ten-Tec.
Surely Ten-Tec could re-introduce this amp with 572B tubes and be VERY
competitive with Ameritron, couldn't they?

 - jgc

John Clifford KD7KGX

Heathkit HW-9 WARC/HFT-9/HM-9
Elecraft K2 #1678 /KSB2/KIO2/KBT2/KAT2/KNB2/KAF2/KPA100
Ten-Tec Omni VI/Opt1
Alinco DR-605TQ
Icom T90A

email: kd7kgx at arrl.net