Jim,
I have a Centaur that came with 3 Svetlana 572Bs when I bought it,
used. After listening to that jet engine of a fan for an hour or so,
I took it out and installed a Dayton #4C548 (W.W. Grainger) 55 cfm,
1800 RPM fan to cut the noise. RadioShack.com also has a 55 cfm fan
(#90-2521) that's a direct replacement. With the 572Bs and slower fan,
I run 600 watts out all day with no heat build up on the cabinet top.
In fact, the only time the cabinet gets even warm is after I shut it
off and the tubes cool down without benefit of a blower. With a 100
watt exciter, maximum output is limited by the input matching network
pad and the lower plate voltage for 811As, so the 572Bs are never
stressed. In its modified state, the Centaur is a great little
amplifier and I use it all the time.
73,
Bill, W9NHQ
----------
> I wonder if anyone has replaced the fan with a slower one,
> 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
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