Need to source Mu-metal cans

[phrarod]

I'm having some interstage transformers made but the manufacturer doesn't have any access to mu-metal cans.

Anyone know where I could find cans roughly 2.25" D x 1.75" H

 

[tinitus]

only mu-metal I have ever seen

Ultraperm MUMetal Shielding Sheet 0.15mm, 31.5cm x 19.5cm 80% nickel | Diy HiFi Supply

 

[phrarod]

I have sheeting but its not as good as a can unfortunately.

 

[jcx]

low carbon steel is lower perm but much cheaper, more available, formable - use a couple iron cans nested with air-space

if its hum you're trying to attenuate then a iron box around the supplies might be a good start

 

[jackinnj]

I have sheeting but its not as good as a can unfortunately.

You wanna demonstrate that with some data?

 

[phrarod]

only real world experience. I would have to somehow weld it into a can shape. Wrapping the transformers did next to nothing. This is why mu-metal cans are used in these applications - Jensen, Audio Note, on and on. Wish I could get away with just mu-metal sheeting. Would make things easier.

 

[max426]

I'm having some interstage transformers made but the manufacturer doesn't have any access to mu-metal cans.

Anyone know where I could find cans roughly 2.25" D x 1.75" H

Check this link. Download the PDF catalog

ZERO Manufacturing, Inc. - Deep Drawn Enclosures

jim

 

[phrarod]

Thanks. I'll check it now.

 

[jackinnj]

only real world experience. I would have to somehow weld it into a can shape. Wrapping the transformers did next to nothing. This is why mu-metal cans are used in these applications - Jensen, Audio Note, on and on. Wish I could get away with just mu-metal sheeting. Would make things easier.

Which mu-Shield foil are you using? You can wrap several layers on a former, insulated from the transformer. Separate each layer (you can use mylar tape) I've had very good luck with MuShield.

Have you identified the source of the radiation? Perhaps changed the orientation of the source? Shielded the source with absorptive material. I have an EMI sniffer which will pick up line radiation and an RFI sniffer -- in particular, the EMI sniffer can be hooked up to a selective voltmeter (I have it on a HP Spectrum Analyzer) and you can pinpoint the source of the radiation.

 

[phrarod]

I have not tried that but would love to try those sniffers. Are they expensive?

 

[jackinnj]

I have not tried that but would love to try those sniffers. Are they expensive?

It's just an antenna -- here's one example -- see also AN-118 at Linear Tech http://cds.linear.com/docs/Application Note/an118fa.pdf

 

[phrarod]

Very cool. I'll look into it.

 

[infinia]

Hi jackinnj
Good link! hadn't seen that yet ...ole JW & BC are my hero's

 

[jackinnj]

One thing which I like about the mu shield company is they suggest "try something cheaper first" -- even a dog-food can (or tomato paste!) will work.

 

[phrarod]

I tried many things but the cans were the only solution in this application.

 

[benb]

Not cans so it's probably not what you want, but there are sheets here at the "ultraperm" entries:
Rare and Esoteric-The Electronic Goldmine
Maybe the 100 sheets would be enough...

And yes, the "something cheaper" might be several/many steel cans, fitting together like Russian dolls, like in this shielding box shown here:
Mu-metal - Wikipedia, the free encyclopedia

 

[phrarod]

Thanks! I'll check all of it out.

 

[jacco vermeulen]

only mu-metal I have ever seen

see : Burklin.com, pag H121.260
They used to carry up to 4.3" diameter x 2.5" height cans, but at $150 each there's not enough demand for that stuff anymore.
I sometimes find large MU cans at NOS places, entertaining part is that 2 out of 3 the vendors are unaware of the intended purpose and/or the original pricing.

 

[phrarod]

Thanks for the tip. But at that price I can get some nice ones with transformers in them from Audio Note. I'll try for surplus places. Haven't thought of that.

 

[jacco vermeulen]

But at that price

Most are unaware how costly MU cans are.
Not that expensive considering the wall thickness though.