Tom,
I'm pretty sure that the hum is mechanical, caused by vibrations of the
transformer inside the supply being amplified by the metal case. You might
try placing the supply on a thick piece of foam, keeping in mind that you
don't want the four feet to sink too deeply into the foam, which would block
circulation and probably give you a problem that would make you long for the
good old days when you were being annoyed by the hum. I suppose you could
open the supply up and try to isolate the transformer from the case, but
that sounds like a lot of work, and I don't think you'll get much for your
efforts. Bottom line: don't worry about the hum as long as it's not the
result of bad filter caps or poor voltage regulation (and from what you've
said, I don't think it is).
Steve
----- Original Message -----
From: "Tom Behler" <[log in to unmask]>
To: <[log in to unmask]>
Sent: December 11, 2015 20:45
Subject: Question on New RS35 Metered Power Supply
> Hi, everyone.
>
>
>
> Well, I got my new Astron RS35 metered linear power supply yesterday, and
> set it up tonight here in my home shack.
>
>
>
> Everything seems to work well, in that I get the output power readings I
> would expect on resonant HF frequencies via my TS590, and on VHF/UHF
> frequencies via my TMV71A.
>
>
>
> I have noticed something, though, that I could use some input on.
>
>
>
> For some reason, this new RS35 has a bit of a louder hum than I noticed
> with
> my older unit.
>
>
>
> Has anyone noticed this sort of thing with the newer RS35's, and if so,
> were
> you able to do anything to address the issue?
>
>
>
> I might consider moving the supply to another location, because right now,
> it is on a shelf just above my operating position. However, I will need
> to
> be certain that the newer location gives the supply sufficient space for
> ventilation.
>
>
>
> I am not sure the problem is significant enough to return it to HRO, but I
> would be curious if anyone has had a similar experience, at least
> recently.
>
>
>
> Tom Behler: KB8TYJ
>
>
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