[TenTec] Amp questions...

[John Clifford]

I am the proud owner of a new-to-me Ten-Tec Centaur amplifier... and of
course I have no idea how to use it.  I thought long and hard before buying
an amp, but decided that since the sunspot cycle is decreasing and thus the
bands are going to get worse for several years before they get better, I
didn't want to sit and not be able to work stations that I can hear (I
already run into that).  Plus, the price was just too good.

I do have a manual and understand the mechanics of adjusting the amp (and am
sure I can do that), but why do I have to tune the amp?  Do the Tune and
Load capacitors act as sort of an antenna tuner to match the amp's output
impedance with that of an antenna?  If so, then why don't these controls
stay at the same setting if antennas on different bands have a 1:1 SWR (or
identical SWR) such as can be obtained via an antenna tuner?

Also, why does this amp need 90 watts of input power to reach full power
(besides FCC requirements limiting gain)?  Is there any way to make the amp
reach full power on 50 watts, or 25 watts (and then I won't raise output
power past that value trying to get more out of the amp... I just don't see
the use in running the exciter wide open when I have an amplifier for that).

Why did Ten-Tec discontinue this amp?  I believe the Ameritron AL-811 is the
best selling amp they have... and the Centaur offers features (QSK, etc.)
that aren't standard with the Ameritron.  I've heard that the tubes were no
longer available for this amp, but if Ameritron can get 'em then why can't
Ten-Tec?

I have an MFJ 300w manual tuner that I will use with the amp at low power
(200w or less, according to my external meter) until I can pick up a
higher-rated tuner.  I just have to play with the thing.  I read the recent
review of the 238A in QST... what is the difference between the 238, the
238A, and the 238B besides cosmetics?  Anyone have suggestions on a good
tuner that isn't one of these models?

Finally... if a crow is sitting on my wire antenna and I light the fire,
will I cook it?

 - 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

email: kd7kgx@arrl.net