Thanks for all the input and suggestions on the problems I have noticed with
my Centaur Demo 411 amplifier.
I was hoping to save a dollar by getting an easy answer from someone who had
had the same problems, but what I found from the group was that although a
few people have had minor problems, none have seen one behave exactly like
mine. All those who have had problems have had them resolved by contacting
TT Technical Support, so Monday morning I did just that. Service Manager,
Paul Clifford told me a few things which had been put into a manual update
which I did had not received. A few of these are:
Correct fuse size for 240v operation.
Revised tune up proceedure.
Ten Tec now conciders the WARNING!!in Paragraph 2.5.2 on page 2.3 of
the manual to be "ambiguous" in that it warns one not to allow plate current
in excess of 550 mA for more than five seconds nor to allow grid current in
excess on 150 mA, when they meant to allow plate currents up to around 750
mA in the tuning process, but not for more than five seconds at a time.
Higher plate current allowed my amp to acheive higher output power on 20
meters and below, but the problem on the highter bands is still there.
I very quickly got used to the blower noise (a "problem" I did not mention,
but which others did). The "THUNK" at power up is indeed from the steel
sheet-metal top. If I place my index finger on the top and hit the power
switch with my middle finger that "problem" is gone. The scratches are
really minor and what one would expect when buying a demo. The arcing and
low power on the high bands remain as problems with the amp I got.
Paul Clifford would like for me to send this amp back at Ten Tech's expense
for them to go over again. They did get a batch of out of spec. plate
capacitors, and thought they had found them all. They are also willing to
be flexible with the month's trial period. I do not know how anyone could
be more fair and up front that that!
I will post a final follow-up once this amp has been fixed...but I know from
experience what the final report will be. Ten Tec will make it right.
73,
Paul Helbert - Wv3j
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