[Amps] Fan Noise in GS-35b Amplifiers

[John G3UUT]

A possible blower you could consider is the EBM Papst G1G108-AB17-02, 
this is capable of over 100 CFM at low pressures and could well be 
adequate if you are not going to push things too hard.  The good thing 
about it is that the speed can be controlled by an external DC voltage 
or resistor network which means it's possible to easily implement 
schemes to reduce the speed / noise when the temp of the outlet air is low.

I've never actually used one of these these blowers but had it in mind 
for an amp I've been planning so don't blame me if it's really noisy.  
However I don't think it's likely to be too bad because; a) its a 
diecast spiral and in my experience these are quieter than sheet metal 
and b) My experience with Papst blowers and fans has been very 
positive.  Anybody else tried them?

If all else fails just cook the thing like the rest of us do, the GS35b 
is just about the most rugged valve there is and they are not too 
expensive either and if you really fry it you can get your money back on 
the cooler at the scrap metal dealer.

Have fun
John G3UUT

On 19/02/2014 16:07, 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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