boji

Re: mu metal in the well...
« Reply #20 on: July 12, 2020, 02:34:12 PM »
Quote
The buses all run under with layers of aluminum for shield but the 4 powersuppies were inductive when under the console.  Wire from the supplies are 16ga except for the ground wires that are 8ga.
My goodness, 4 supplies, each with an 8ga com?  How many channels? I  thought I was over compensating, but compared to your setup, might be the other way around.

Reviewing some broadcast console setup manuals, the earth ground is given a special run of its own, directly from the control room mains, tied to the frame with a big lug terminal. From there, PSU grounds are stacked at this point.  From the other side of this lug is a run to the broadcast console's backplane agnd.  Coms read like a star ground but with hefty wire!
Edit: Forgive these basics, this is new to me when it comes to actual implementation.

For my frame's power delivery, I'm treating the copper distribution bars as the "backplane's backplane" i.e.  From these bars, up to each bucket's 500 series and channel backplanes with 18ga.  But it sounds like com returns leaving the copper bar should be increased in gauge, and have its own run to a lug post, circumventing the amphenol connector.

Quote
for shielding - "mumetal" preferably but it's not really practicable or affordable...
Practically distance is your friend - as you found - and twisted pair / differential electronics for good CMMR.
  Thanks Newmarket, I'll for sure try distance before considering investing in costly shielding.
« Last Edit: July 12, 2020, 02:59:58 PM by boji »


boji

Re: mu metal in the well...
« Reply #21 on: July 12, 2020, 02:56:53 PM »
Would using something like this at the back of the frame where all coms come together be useful?

https://www.amazon.com/Fastronix-Premium-Current-Terminal-Connectors/dp/B079K5HB79


Newmarket

Re: mu metal in the well...
« Reply #22 on: July 12, 2020, 03:04:31 PM »
  Thanks Newmarket, I'll for sure try distance before considering investing in costly shielding.

Cheers. And "costly" is something of an understatement when it comes to mu-metal.
Also - to add to the 'fun' -  it needs to be re-annealed after working it if you want to get the full advantage.
Although it still has a significant effect even if you don't.
fyi I used to use it when I worked in electronics development for Surface Science instrumentation.

boji

Re: mu metal in the well...
« Reply #23 on: July 12, 2020, 03:14:54 PM »
Woah, this kinda work?   :o
https://en.wikipedia.org/wiki/Surface_science



At what temp / duration?  Got me a blowtorch, not a kiln.  Let's hope it does not come to this.  ;D

abbey road d enfer

Re: mu metal in the well...
« Reply #24 on: July 12, 2020, 04:52:40 PM »
At what temp / duration?  Got me a blowtorch, not a kiln.  Let's hope it does not come to this.  ;D
Annealing mu-metal is a very specialeized process that requires controlled heating and cooling in a magnetic field in hydrogen atmosphere. Not something you can do in your garden shed.  ;)
Who's right or wrong is irrelevant. What matters is what's right or wrong.
Star ground is for electricians.

JohnRoberts

Re: mu metal in the well...
« Reply #25 on: July 12, 2020, 07:27:04 PM »
Annealing mu-metal is a very specialeized process that requires controlled heating and cooling in a magnetic field in hydrogen atmosphere. Not something you can do in your garden shed.  ;)
Yup just don't put your torch to it inside the hydrogen... ::)



JR
Don't only half-ass tune your drums. Visit https://circularscience.com to hear what properly "cleared" drums sound like.

boji

Re: mu metal in the well...
« Reply #26 on: July 12, 2020, 09:30:19 PM »
Quote
requires controlled heating and cooling in a magnetic field in hydrogen atmosphere.

Oh jeeze. Yeah um, I like having eyebrows, I think I'll pass.  ;D   

What on earth is the hydrogen doing, relieving surface tension for molecular redistribution during high heat? Is the magnetic field applied like a gaussian paint brush or is it a steady field? So many q... no blimp rides for me.

« Last Edit: July 13, 2020, 02:58:57 AM by boji »

Newmarket

Re: mu metal in the well...
« Reply #27 on: July 13, 2020, 04:48:20 AM »
Woah, this kinda work?   :o
https://en.wikipedia.org/wiki/Surface_science

Yes - that's the field. although I'll point out I was on the electronics side of it rather than the physical / chemistry application.
So basically designing around HV supplies for electron acceleration / polarisation plates etc etc for this sort of kit

https://scientaomicron.com/en/productDetailPages/system-solutions/electron-spectroscopy/NanoESCA

But getting back to screening - as discussed here - it's not generally used or deemed necessary for audio except for eg transformer screens.


 

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