Stillpoints ERS cloth for EMI/RFI

Ptss wrote,

"Are you saying the magnetic field from the transformer contributes as much noise as EMI/RFI?"

I'm saying it contributes more.

"Does wrapping with mu-metal cause any problems?"

Mu metal is conductive so one needs to be soemwhat careful. Usually the transformer is easily wrapped

"I also have a ~ 75 pound Equitech 2Q transformer. They don't appear to have it enclosed in mu-metal Any idea why?

My guess is either they don't know or don't care. I can't think of any manufacturers who enclose the transformer in mu metal. Go figure. Of course they don't do a lot of things, E.g., better fuses in, better power cords.

Thanks Geoffkait. I'll contact Equitech monday and post info.

I've used mu metal in a couple of DIY projects with good results. I also covered the transformer inside my Lamm LL2 preamp and cannot hear a difference. Maybe it is shielded well enough already.

About a year ago I wanted to tackle EMI/RFI inside my digital: Metrum Octave DAC, Audiophilleo and purpose-built PC. At the time I was advised to try 3M EMI Absorber AB5100S instead of ERS cloth. My recollection of the reasons were better performance and that ERS cloth, being cloth, exposes us to the risk of loose conductive fibers inside an electric appliance - must be handled with care.

I bought the 3M "paper". It's not paper, really. It's 1mm thick, doesn't bend, and it's heavy. And worked very well for me. The edges are also conductive, so you want to line them with tape. Never used ERS so can't comment on it.

In my DAC, PC and AP I covered 3 faces of the box: one of each parallel faces inside the box. Also applied small pieces around clocks, integrated circuits, etc. around clocks I applied several layers. I wasn't patient enough to try out various combinations of varying layers in different places. But the impact was positive and noticeable. I crafted a box around my PPA USB card, taped it with vinyl tape, tripple-layered on top of it's clock, etc.

Another nice place to try this was in the circuit breaker box, on the inside of the box door, right in front of the circuit breakers themselves.

Very good product. A lot of user input over at JPlay/Computer Audio forum. Many DIY hard-core explorers there.

Never had luck with ERS, oh! well. Too phasey for me. But I did have good results with the 3M AB5100S on the AC cord coming into the player, on ribbon cables inside the player, those weird short 12 wire connectors, also on chips. Two layers of mu metal all around the transformer is noticeably better than one layer, but leave a space of say 1/4 between layers. I also strongly recommend pure natural cork 1/8" thick under any transformer and remove the bolt or at least loosen it. The bolt is a good idea only for shipping. It couples the 60 Hz hum to the chassis. Hel-loo! Finally, 1/8" cork spacers should be placed below all circuit boards. You know, to isolate them from the stupid transformer.