Head-Fi.org › Forums › Misc.-Category Forums › DIY (Do-It-Yourself) Discussions › Is there something wrong with this picture?
New Posts  All Forums:Forum Nav:

Is there something wrong with this picture? - Page 3

post #31 of 37
2/22/09 at 6:40pm
Another thing to consider. The toroid will leak EMI/RFI the most where the leads connect due to a break in the windings. This should point away from sensitive circuits.
Reply
post #32 of 37
2/22/09 at 6:53pm
Don't they leak the most through the axis, the direction of the bolt? Either way it looks like given that case, the transformer is turned as much as possible. I suppose a belly band could help a little, if it matters, but will regular steel be very effective as one? I thought about taking a steel coffee can, cutting the top 2/3rd off, painting it and putting a transformer in it. It would have to be isolated electrically at either the top or bottom, or it would be another way to create a shorted-turn problem.
Reply
post #33 of 37
2/22/09 at 9:15pm
^Something like this maybe?
Reply
post #34 of 37
2/22/09 at 10:18pm
^ but those are aluminum, I was thinking something rather ferrous like steel.

Edit: I may be wrong, looking at them a 2nd time they only mentioned the lid is aluminum but nothing about the rest, and the square ones higher up on the page do specify steel except for the lid. With the lid not being steel, it almost seems it would be better to drill a few addt'l holes in it for more airflow, though I suppose it's not that big of an issue, since nobody should be pushing the limits of their transformer that much.

One thing I'm not clear on with those is how they mount. Looks like the "cover" is the base since it has the holes, but then how does the top stay on, is it threaded or does it need to be strapped down somehow?
Reply
post #35 of 37
2/22/09 at 11:13pm
Thread Starter 
My understanding is that you want something with as high a permeability as you can afford/acquire.
Here's a table of common metals:
Permeability (electromagnetism) - Wikipedia, the free encyclopedia

I believe mu-metal was specifically engineered for magnetic shielding. However afaik it is very expensive.

EDIT - checked and yes mu-metal was developed for shielding. There is a cool story behind it if you read the wiki.
Reply
post #36 of 37
2/22/09 at 11:25pm
Agreed, but until it's known whether there is EMI, it could be a practical limit on how much to spend, also considering there are other transformers with belly bands or already having an enclosure that may cost little if any more than original transformer plus mu-metal bought separately. The beauty of using a steel can is they're quite common and free when you buy whatever is inside of one.
Reply
post #37 of 37
2/23/09 at 12:13am
Thread Starter 
In this case there is no hum at all. There is some hiss at volumes far above listening levels, but I attribute this to using a single ended output (no common mode noise rejection), and usb noise.
Reply
New Posts  All Forums:Forum Nav:
  Return Home
Head-Fi.org › Forums › Misc.-Category Forums › DIY (Do-It-Yourself) Discussions › Is there something wrong with this picture?