[TenTec] Centaur cooling mod for lower noise?

[Duane A Calvin]

Jerry,
        Carl's answer is the short and sweet one.  I had an interesting
exchange of letters with the TT president about the Centaur when it came
out and I documented the noise level in my shack caused by it.  No help. 
However, I did take it in to the acoustic lab where I work and had one of
their engineers look it over.  I had noticed that with the covers off,
the fan was relatively quiet, but if you put anything close to the fan
intake, it got very noisy very quickly.  The engineer agreed and said it
was the shock wave (if I'm remembering it correctly) from the leading
edge of each fan blade which was striking the slot openings in the
cabinet side (which is, essentially, too close to the fan).  Sort of like
playing cards on a spoked bicycle wheel.  The best answer is to do what
Carl did and remove the material in front of the fan, or, as one fellow
did, use a pair of pliers and "twist" each of the bars so that it takes
on a 45 degree (or so) angle.  The latter option will reduce, but not
eliminate the noise.  I took the more expensive route, and traded my
Centaur on a Centurion.  No more noise - hi!

        73,  Duane


On Sun, 18 Jun 2006 14:38:45 -0700 Jerry Volpe <kg6tt at arrl.net> writes:
> Have you found a way to quiet down your Centaur?
> 
> I have probably used my Centaur 5 hours in the past year. Not that 
> it is 
> a bad amp. It is a NOISY amp. I'd love an opportunity to quiet it 
> down. 
> But as I look at the physical layout I can see that simply going to 
> a 
> 'softer' cooling fan is not a viable answer as the fan must push 
> sufficient quantities of air over one tube to the next and then 
> finally 
> to the last tube. Too bad Ten-Tec didn't put three small fans on the 
> 
> rear panel each pushing air over its own tube and then exhausting 
> thru 
> the top cover. Well it is what it is.
> 
> On the other hand placing a temperature sensor near the final tube 
> and 
> using that sensor to 'spin up' the existing fan only as needed  but 
> keep 
> that fan in a much slower mode the rest of the time might be the 
> answer. 
> I am sure that I am not the first to consider this. Rather than 
> re-invent an existing wheel I am seeking others who have 
> successfully 
> modified a Centaur. Did you keep the details? Willing to share 
> them?
> 
> I have only found one reference to this type of Centaur mod on the 
> web 
> and it is a French site. Somewhat useful nevertheless.
> 
> 73,
> Jerry, KG6TT
> Fairfield
> _______________________________________________
> TenTec mailing list
> TenTec at contesting.com
> http://lists.contesting.com/mailman/listinfo/tentec
> 
> 
 
 
--------------------------------------
Duane Calvin, AC5AA
Austin, Texas
 
http://home.austin.rr.com/ac5aa