OT: Astron RS-35M Transformer Hum

[inventor61 .]

I have a CAD design for a replacement wooden top for the RS-35, -35M, and
VS-35M Astron supplies.  This top cover looks exactly like the factory
steel cover, uses the same mounting holes, and even has an exact duplicate
of the vent slots.
The material that worked out best was a HDF board.  It can be painted
easily in any color including the factory textured black.
The design is intended to be produced on a CNC machine like a full size
ShopBot, as were the several prototypes, which really turned out splendidly.
It of course solved the problem of the eddy currents in the steel lid,
which for this size Astron is too close to the field of the power
transformer.  These currents cause the acoustic noise.
I was planning on bringing this replacement top cover to the ham operator
market last year but I ran into production challenges.  It's simply too
costly to produce these, ship them, and sell at an acceptable cost even
ignoring making a worthwhile margin.

If someone has a better idea than mine for making these, I am all ears.

Steve KZ1X
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[Nate Bargmann]

* On 2020 24 Apr 11:50 -0500, inventor61 . wrote:
> If someone has a better idea than mine for making these, I am all ears.

No better idea.  I've read in times past of someone sandwiching some
compressible material between the transformer and the supply top cover
to quell or reduce the hum.  I have an RM-50M that hums in this manner
and fortunately it is not loud enough to keep me from listening to the
K3 at about 8 o'clock with external speakers.

73, Nate, N0NB

--

"The optimist proclaims that we live in the best of all
possible worlds.  The pessimist fears this is true."

Web: https://www.n0nb.us
Projects: https://github.com/N0NB
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[Clay Autery-2]

Actually, I have had MUCH more success in isolating the transformer
mechanically from the chassis with the aforementioned Sorbathane.
https://www.sorbothane.com/Data/Sites/31/pdfs/product-guides/Sorbothane-SPG.pdf 
<---- catalog of standard products.

I use isolation studs.... they have metal fasteners to attach to chassis
and interior components (transformer primarily), but there is a
mechanical decoupling via the Sorbothane material.
Alternatively, you could use a sheet of Sorbothane underneath the
xformer foorprint and a sheet between the xformer hold down clamp and
the xformer body.  The principle is

1) Isolate the xformer from the metal chassis...
2) Include enough material mass at the right durometer to convert the
vibrations (and audible accompaniment) into heat, et al.

Used to use small isolation studs to mount the 10k RPM Barracuda drives
in 10-drive arrays in large CalPC steel towers....  Made them whisper
quiet AND protected the drives from shock as well.

73,

______________________
Clay Autery, KY5G
[phone]

On 04/24/20 15:07, Nate Bargmann wrote:

> * On 2020 24 Apr 11:50 -0500, inventor61 . wrote:
>> If someone has a better idea than mine for making these, I am all ears.
> No better idea.  I've read in times past of someone sandwiching some
> compressible material between the transformer and the supply top cover
> to quell or reduce the hum.  I have an RM-50M that hums in this manner
> and fortunately it is not loud enough to keep me from listening to the
> K3 at about 8 o'clock with external speakers.
>
> 73, Nate, N0NB
>

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[Keith N6JPA-2]

You should purchase an Astron Switching power supply. They are well

made and filtered properly. I use a SS-25M that has a fan that runs at
times,

but it is not too loud.

On 4/24/2020 9:48 AM, inventor61 . wrote:

> I have a CAD design for a replacement wooden top for the RS-35, -35M, and
> VS-35M Astron supplies.  This top cover looks exactly like the factory
> steel cover, uses the same mounting holes, and even has an exact duplicate
> of the vent slots.
> The material that worked out best was a HDF board.  It can be painted
> easily in any color including the factory textured black.
> The design is intended to be produced on a CNC machine like a full size
> ShopBot, as were the several prototypes, which really turned out splendidly.
> It of course solved the problem of the eddy currents in the steel lid,
> which for this size Astron is too close to the field of the power
> transformer.  These currents cause the acoustic noise.
> I was planning on bringing this replacement top cover to the ham operator
> market last year but I ran into production challenges.  It's simply too
> costly to produce these, ship them, and sell at an acceptable cost even
> ignoring making a worthwhile margin.
>
> If someone has a better idea than mine for making these, I am all ears.
>
> Steve KZ1X
>

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[Phil Kane-2]

On 4/24/2020 2:15 PM, Keith N6JPA wrote:

> You should purchase an Astron Switching power supply. They are well
> made and filtered properly. I use a SS-25M that has a fan that runs at
> times, but it is not too loud.

I use a SS-50M and "not too loud" is a matter of judgment.  It is
located on top of my power distribution rack, about 6 feet beside me and
2 feet above my head.  The fan kicks on every time any of my
transceivers goes into transmit mode in full power, which is distracting
as well as the fan noise gets picked up by the desk mic.  But it is far
more reliable than the MFJ supply that it replaced.

73 de K2ASP - Phil Kane
Elecraft K2/100   s/n 5402

From a Clearing in the Silicon Forest
Beaverton (Washington County) Oregon
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[Dale Boresz]

I have a stack of QST magazines from 1996 resting on top of my Astron
VS-35M. No transformer hum at all!

Have not tried magazines from any other years, so YMMV...

73,
Dale - WA8SRA

On Fri, Apr 24, 2020 at 4:09 PM Nate Bargmann <[hidden email]> wrote:

> * On 2020 24 Apr 11:50 -0500, inventor61 . wrote:
> > If someone has a better idea than mine for making these, I am all ears.
>
> No better idea.  I've read in times past of someone sandwiching some
> compressible material between the transformer and the supply top cover
> to quell or reduce the hum.  I have an RM-50M that hums in this manner
> and fortunately it is not loud enough to keep me from listening to the
> K3 at about 8 o'clock with external speakers.
>
> 73, Nate, N0NB
>
> --
>
> "The optimist proclaims that we live in the best of all
> possible worlds.  The pessimist fears this is true."
>
> Web: https://www.n0nb.us
> Projects: https://github.com/N0NB
> GPG fingerprint: 82D6 4F6B 0E67 CD41 F689 BBA6 FB2C 5130 D55A 8819
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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>
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> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>

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[Jim Rhodes-2]

Yes, '96 was a quiet year alright.

On Fri, Apr 24, 2020 at 6:22 PM Dale Boresz <[hidden email]> wrote:

> I have a stack of QST magazines from 1996 resting on top of my Astron
> VS-35M. No transformer hum at all!
>
> Have not tried magazines from any other years, so YMMV...
>
> 73,
> Dale - WA8SRA
>
> On Fri, Apr 24, 2020 at 4:09 PM Nate Bargmann <[hidden email]> wrote:
>
> > * On 2020 24 Apr 11:50 -0500, inventor61 . wrote:
> > > If someone has a better idea than mine for making these, I am all ears.
> >
> > No better idea.  I've read in times past of someone sandwiching some
> > compressible material between the transformer and the supply top cover
> > to quell or reduce the hum.  I have an RM-50M that hums in this manner
> > and fortunately it is not loud enough to keep me from listening to the
> > K3 at about 8 o'clock with external speakers.
> >
> > 73, Nate, N0NB
> >
> > --
> >
> > "The optimist proclaims that we live in the best of all
> > possible worlds.  The pessimist fears this is true."
> >
> > Web: https://www.n0nb.us
> > Projects: https://github.com/N0NB
> > GPG fingerprint: 82D6 4F6B 0E67 CD41 F689 BBA6 FB2C 5130 D55A 8819
> >
> > ______________________________________________________________
> > Elecraft mailing list
> > Home: http://mailman.qth.net/mailman/listinfo/elecraft
> > Help: http://mailman.qth.net/mmfaq.htm
> > Post: mailto:[hidden email]
> >
> > This list hosted by: http://www.qsl.net
> > Please help support this email list: http://www.qsl.net/donate.html
> > Message delivered to [hidden email]
> >
> ______________________________________________________________
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>

--
Jim K0XU
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[Clay Autery-2]

LOL!  That's funny!

73,

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Clay Autery, KY5G
[phone]

On 04/24/20 18:21, Dale Boresz wrote:
> I have a stack of QST magazines from 1996 resting on top of my Astron
> VS-35M. No transformer hum at all!
>
> Have not tried magazines from any other years, so YMMV...
>
> 73,
> Dale - WA8SRA
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