Yes, that Dayton blower is a good one to use, however, it is still quite loud
even with the slower speed. Of course, you can reduce the fan speed on
receive, but when transmitting, the noise is objectionable. I'm wondering if
slower speed and higher volume really translates to adequate cooling if the
actual air pressure is not there. Many blowers will provide what seems to be
adequate air flow, but with back pressure, just don't provide sufficient flow.
I have seen several European hams' GS-35b amps with what look like just
"muffin" type fans. Those things are pretty loud anyway and I don't think they
move enough air. I have seen examples, also where they are using two "muffin"
type fans.....one above the anode cooler pulling air out of the enclosure and
one below the chassis blowing upward thru the tube. There has to be some of
you folks out there who have a "quieter" solution??
73, Jack, W9GT
________________________________
From: N1BUG <paul@n1bug.com>
To: Jack C. Shutt <w9gt@frontier.com>; "amps@contesting.com"
<amps@contesting.com>
Sent: Thursday, February 20, 2014 9:26 AM
Subject: Re: [Amps] Fan Noise in GS-35b Amplifiers
I don't know what the "recommended" blower is, but bear in mind slow speed
blowers can be much less noisy than high speed ones. They tend to be physically
larger, however. On some prior amps I used high speed (2500-3000 RPM I think)
blowers that were physically rather small. They got the job done but were very
noisy. On my current generation 4CX1500B amps I use Dayton 2C647 blowers. They
run at 1500 RPM, but move about the same amount of air by using a larger
squirrel cage. They are much quieter. I suspect even this amount of noise would
be objectionable to many people but those blowers are far less noisy than the
4" fan in my rack mount server case that houses the shack PC. Something has to
be done about that fan!
73,
Paul N1BUG
On 02/19/2014 11:07 AM, Jack C. Shutt wrote:
> I have gathered from all the info that I have read on amps using
> the GS-35b that a healthy air flow is necessary to keep these
> tubes happy. Unfortunately, the 100 CFM squirrel cage blower
> that is recommended for this purpose is quite noisy. Any
> suggestions for an effective cooling arrangement that is quieter?
> I thought about remotely locating the blower and using a hose
> duct to the amp, but this is just not practical in my shack.
> Suggestions? 73, Jack, W9GT
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