[sdiy] shielding question

[Harry Bissell]

Try Mumetal shielding. Best is to make a complete turn around the power transformer, 
if possible. DON'T get it too close or it will get VERY hot (if there is a lot of
flux leakage)

Its possible that a flat sheet on top of the offensive unit might be effective, but
you really want a complete path for the flux to run around in.

you might try to shield the receiving coils (inside the reverb) as well.

DON'T get too close to any magnetic pickup. Ask me about the time I made a mu-metal
shield for an ARP Avitar hex pickup (to stop the 60Hz um). Describing WHY that was
a really really BAD idea is left to the reader...   :^)

H^) harry


http://www.goldmine-elec-products.com/prodinfo.asp?number=G16600A&variation=

----- Original Message -----
From: Andre Majorel <aym-htnys at teaser.fr>
To: synth-diy at dropmix.xs4all.nl
Sent: Fri, 25 Jun 2010 05:14:11 -0400 (EDT)
Subject: Re: [sdiy] shielding question

On 2010-06-24 17:35 -0400, Travis Thatcher wrote:
> On Thu, Jun 24, 2010 at 5:15 PM, Andre Majorel <aym-htnys at teaser.fr> wrote:
> > On 2010-06-24 04:37 -0400, Travis Thatcher wrote:
> >
> >> I am trying to put together a live rack consisting of (in top to
> >> bottom on the rack):  furman power conditioner, motu2408mkII,
> >> patchbay, roland gr-1 reverb, diy tb3031 + tbDac.
> >>
> >> before the reverb was fine, sitting on top of the rack. in this
> >> configuration there's noise as it is resting on the 3031.  i can move
> >> it up a space, but still some nice hum. when i turn off the 3031, the
> >> hum is gone. all power is connected to the furman conditioner.
> >
> > A wild guess : the TB-3031 is powered by an EI transformer and the
> > enclosure is made of aluminium ?
>
> yeah

Then there's nothing to stop the magnetic field that it leaks.
Perhaps some strategically placed sheet steel would help. The
thicker the better.

Toroidal transformers are supposed to have less leakage.

-- 
André Majorel http://www.teaser.fr/~amajorel/
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-- 
Harry Bissell & Nora Abdullah 4eva