[TenTec] Modifying the Centaur

[James Parsons]

Hi, Gang...

I have a Centaur amplifier that I bought new from TT some years ago. It
has been a faithful performer (except for those cheap switches), but it
sure does suffer from high fan noise. It seems that 100 CFM is a lot of
air to move across those tubes. I built a lot of amplifiers during my 58
years of hamming, and a number of them were 811 type, but I never blew
that much air across them.

I wonder if anyone has replaced the fan with a slower one, or maybe put
a series resistor in the line with the existing fan? I need to do
something because the constant blower noise over a  period of operating
hours is sure tiring. It seems my options are:

1. Replace the fan with a slower one (will the tubes get too warm?)
2. Slow the fan down.(how many CFM?)
3. Disconnect the fan and use some muffin fans on the top of the
cabinet, blowing towards the tubes.
4. Replace the 811 tubes with 572B tubes and much less cooling.

I have found that changing the mounting of the fan, as some have
suggested, has not worked.

Has anybody done anything about this? I have never figured out why TT
found a need for 100 CFM for 811 tubes unless it is the way the fan had
to be mounted and the fact that the tubes are in a line of three in a
horizontal plane with the fan.

I would like to hear from anyone who has ACTUALLY made a modification to
this amplifier for this purpose.

Thanks and 73 de Jim, K5ROV
-- 
James (Jim) Parsons, K5ROV   USAF, Ret. Ham for 58 yrs.
k5rov@wcc.net     QCWA, ARCI, Fists, ARRL, ARMS
EX: W1RLA, K5FBB, K4FEO, SV0WN (CRETE), SV0WN (RHODES),
DL4NC, DL4JP, KA2FC (JAPAN), KA2JP (JAPAN).
JOHN 3:16

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