My laser printer has the same effect.
-de John NI0K
Robert Sands wrote on 4/24/2020 10:17 AM:
My Astron hums loudly only when the fax machine runs. Otherwise silent.
?interaction puzzling.
On Fri, Apr 24, 2020, 7:35 AM David Bunte <[email protected]> wrote:
David -
I have an RS-35M, that sits on a shelf under my operating desk. I leave it
on 24/7, and never gave any thought to acoustic hum from it. I just ducked
my head down below the desktop, and 'thought' I could hear some hum. I
turned off the power supply and verified that there is a little bit that I
could detect. I am blessed with better than average hearing for a
76-year-old, but that is largely thanks to my hearing aids.
In the past I have had pretty bad hum from power supply transformers, and
the worst case I ever had was totally cured by tightening the bolts that
held the laminations together. That was pretty easy because it was an open
frame transformer in a home brew KW amp. In a number of transformers I have
paid attention to in the past few years, the screws or bolts that hold the
transformer to the chassis go through the corners of the laminations, and
tightening those may also help.
I have been "told" that acoustic hum is often made more evident because the
chassis is vibrating... and that putting some dampening material (a sheet
of rubber for example) under the transformer goes a long way toward
reducing the problem.
Best of luck.
Dave - K9FN
On Fri, Apr 24, 2020 at 10:14 AM David Herring <[email protected]>
wrote:
Does anyone have a way to dampen the physical hum generated by the
transformer in an RS-35M PS?
This really is just transformer hum I’m hearing, not signal hum…my
station
is fully bonded and as a result quiet in that regard. Most folks
probably
never hear this hum, but I have been “blessed” with really good hearing
and
so this hum irritates the dickens out of me.
If push comes to shove, I will relocated the PS farther away from the
operating position, I just didn’t want to have to extend power and
bonding
runs and thus am hoping someone has a different idea.
Thanks & 73,
David N5DCH
(Formerly AH6TD)
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