If I had that issue on either my 35 or 50, I'd do similar, but I would
use the Sorbathane purpose built isolators of the correct dimensions as
per the engineering doc.
I started out making my own isolators with raw Sorbathane sheet stock,
It's phenomenal when you mmatch the right material to the application,
and get the design right.
I won't use anything else.... transformers, HDD, etc...
73,
Clay E. Autery, Jr.
KY5G
On 9/29/2023 4:11 PM, Steve Lawrence via Elecraft wrote:
Astron RS-35M Hum (and probably other Astrons).
I've found some posts in the archives related to this topic so perhaps a bit OT
but hopefully of general interest.
My Astron RS35M developed a hum that increased with increased load. Otherwise
working OK but became annoyingly loud.
My solution was to insert a round rubber pad at each of the four mounting
screws between the chassis and the transformer.
3/4" OD x 1/4" ID x 1/8 inch thick.
https://www.amazon.com/dp/B0BJPF9QMZ
The hum now is very low. Nothing that would otherwise stand out if I weren't
listening for it. And it does not change with load or increased load.
So the problem seems to be mechanical coupling between the transformer and the
chassis with the hum amplified when the cover is on the PS. Likely varies with
any given batch of transformers. My much older RS-35M exhibits no hum at all
even under load.
73 - Steve WB6RSE
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