[Amps] Quieting a Henry 2K Classic X

[Gary Smith]

I like Ron's suggestion of external 
mounting. If you put carpeting inside the 
enclosure, you'll deaden the sound even 
more.

What I did with the Alpha 77 which has a 
user selectable speed via a wire resistor 
& wiper, is to place a normally closed 
thermal switch (125F) in the exhaust and 
run the speed at lowest at all times it's 
idling or little use. When I'm repeatedly 
transmitting & the exhaust temp rises to 
125, the switch closes and it jumps the 
fan connection to maximum. When I stop, 
the fan returns to it's slow setting at 
124F.

I wear Bose Noise cancelling headsets and 
even at high speed, the fan is almost 
invisible.

OTOH, I've thought about removing the 
squirrel cage, removing power to the motor 
and attaching an adequate fan remotely, 
the whoosh of full flow would not be as 
bad as the internal squirrel cage next to 
my head.

Something like this:
https://www.zenhydro.com/ipower-8-inch-inl
ine-fan-770-cfm.html

Of course one would want to compare 
exhaust temps to be sure the external fan 
was doing the job. They do have speed 
controllers, not sure about the RFI 
aspect.

I always liked quiet. I had a desktop 
computer with a loud fan that I used for 
recording. The hard drive and fan 
interfered with the recording so I water 
cooled all the parts with fans. Ran tygon 
tubing to an already quiet Iwaki water 
pump in a sound muffled enclosure at the 
diagonal side of the room, no fan needed. 
By the time the water got back it was room 
temperature. Used two SSD for hard drives 
and the only sound was the fan in the PS. 
I had an oversized PS and it never ran at 
anything but slow speed. Dead quiet...

73,

Gary
KA1J

  
> I have acquired a Henry 2K Classic X (domestic model) amplifier.  It
> uses a pair of 3-500Z's with chimneys. The very loud Dayton blower is
> driving me nuts. The Dayton blower is a model 2C915A, 3020 RPM, 230
> volts and 140 CFM. This same blower is used when the larger Plate
> transformer of the Export model is installed. I suspect that this
> blower is much larger than required when operating at 1500 watts on CW
> or SSB.
> 
> The standard blower in the 2K Classic was a Redmond 80239, 110vac
> unit. I cannot find the specs but I suspect it was around 90 CFM.
> 
> I have researched several articles on about using a pair of 3-500Z's
> and the reference material shows a need for about 13 cfm per tube or
> 26 cfm total. Likewise, a 3-1000Z requires 4 cfm. I am aware that back
> pressure requirements play into this also.
> 
> I read somewhere that it is possible to slow down a blower during
> standby periods by using a "split-capacitor" motor. Perhaps I have the
> phraseology wrong, but what I would like to do is have a blower slow
> down in speed significantly during listening periods and come up to
> speed during TX.  I operate mostly CW, little SSB, and do not use
> break-in/QSK so I could switch relays to do this.
> 
> My other alternative is to install a smaller blower and risk
> shortening tube life. I do not contest very much nor operate
> continuous modes such as RTTY and FT8 at full power.
> 
> Your ideas are welcome!
> 
> 73, Dennis W0JX
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