Protecting "brain" from "braun" - Electomagnetic Shielding sheet £14

Give it a go.  Could be better, could be worse, but no harm in trying.

FWIW, back in the day Naim offered a shielding kit for the NAIT 3 to enable it to run MC boards without picking up too much interference from the transformer. It was a mumetal shielding sheet that was fairly effective with regard to noise but the downside was that overall performance took a bit of a hit.  

Thx Richard. Re it being eyesore sheet will go on underside of rack shelf. Sheet's black or dark grey and rack on floor so no line of sight to this underside

Richard Dane posted:

Give it a go.  Could be better, could be worse, but no harm in trying.

FWIW, back in the day Naim offered a shielding kit for the NAIT 3 to enable it to run MC boards without picking up too much interference from the transformer. It was a mumetal shielding sheet that was fairly effective with regard to noise but the downside was that overall performance took a bit of a hit.  

Hi again Richard. further reflecting on what you said I'm struggling to think how this kind of thing might cause the hit to performance you mention. I was thinking that a seemingly neutral (inert sheet of material) thing like I'm considering could have any negative influence. Could you just elaborate a small bit if you've got any more info?

Sorry G, I'm not expert as to the why. I'm on much safer ground when it comes to the subjective - i.e. discerning what sounds best to me.  Best explained by somebody who better understands the science behind these things.  However, the performance hit was such that Naim were fairly reluctant to offer up the shielding kit unless their arm was twisted and were very clear about the caveat with regard to performance. I've never heard a NAIT 3 with MC cards and the shielding kit, so couldn't say how it impacts performance. Sorry.

I'm mystified but definitely appreciate your information. So there's a hit. Want to find out why to decide if I buy it buy it but also as a general matter of interest. Thx Riichard

Atvtge price you mention, it surely is worth a punt and listen?

Richard Dane posted:

Sorry G, I'm not expert as to the why. I'm on much safer ground when it comes to the subjective - i.e. discerning what sounds best to me.  Best explained by somebody who better understands the science behind these things.  However, the performance hit was such that Naim were fairly reluctant to offer up the shielding kit unless their arm was twisted and were very clear about the caveat with regard to performance. I've never heard a NAIT 3 with MC cards and the shielding kit, so couldn't say how it impacts performance. Sorry.

I'm pretty sure that the presence of a mumetal close to a transformer will deform the distribution of the magnetic field generated by the primary coils and probably lessen the amount of flux coupling with the secondary coils in a non-uniform way. Not only would this reduce the voltage produce by the secondary coils but it may also cause stray voltages and unwanted current loops. 

Naim also  used to offer some current limiting on the NAP250 so ELS panels would not fry...this also caused a sonic  hit. 

Likewise there was a factory sanctioned mod that lessened the ability of phono cards to faithfully pick up Radio Moscow. Another dip in performance too. 

Likewise those rare custom extra length Snaics that they made with great reluctance. Or was this just an urban myth?

Ron Toolsie posted:

I'm pretty sure that the presence of a mumetal close to a transformer will deform the distribution of the magnetic field generated by the primary coils and probably lessen the amount of flux coupling with the secondary coils in a non-uniform way. Not only would this reduce the voltage produce by the secondary coils but it may also cause stray voltages and unwanted current loops.

Hi Toolsie. If the shielding is outside the unit box does this still affect SQ  / does the shape of the magnetic field matter once it gets out of the box?

Selfishly drawing the focus back to my dilemma: a shield sheet on the underside of a rack above the "emmiters" - is this going to give a negative effect?

FYI - two of my jackets, made by an Italian company, have electromagnetic shielding sewn into them, surrounding the left breast pocket.  Maybe with all that sheilding, I’ll ba able to sing better.

An unusual material for a jacket. I'm thinking either you're a shoplifter - perhaps you can stuff tagged goods into your jacket and they won't set off the alarm. Or you have an electromagnetic intolerance like the guy in the new prequel to Breaking Bad.

Oh! sorry thought you were being flippant and so I was in return. Just thought actually you probably have a pacemaker and are ensuring nothing will disturb it. Fair enough. in this case think it's something I'd get

Ron Toolsie posted:

...Likewise those rare custom extra length Snaics that they made with great reluctance. Or was this just an urban myth?

I've heard of such things - up to 3m!  Possibly done under duress, then passed out the back door in the dead of night wrapped in a brown paper bag...

Nope, not a shoplifter - the pocket is just big enough to accommodate a cell phone.  Well, unless I'm thinking of lifting small high end goods like watches perhaps.  Or cell phones.  And I don't have an intolerance to EMR - I'm not convinced that such a malady really exists.  No pacemaker either.  I just found these pockets after I had purchased the jackets, when I noticed tags attached to the zippers.  They're made in Italy - maybe the Italians are onto something they're not talking about.

docmark posted:

Nope, not a shoplifter - the pocket is just big enough to accommodate a cell phone.  Well, unless I'm thinking of lifting small high end goods like watches perhaps.  Or cell phones.  And I don't have an intolerance to EMR - I'm not convinced that such a malady really exists.  No pacemaker either.  I just found these pockets after I had purchased the jackets, when I noticed tags attached to the zippers.  They're made in Italy - maybe the Italians are onto something they're not talking about.

RFID shielding maybe for wallets?

Could be, but I'm working on an alien protection device.  A tinfoil hat is next.

Richard Dane posted:

Ron Toolsie posted:

...Likewise those rare custom extra length Snaics that they made with great reluctance. Or was this just an urban myth?

I've heard of such things - up to 3m!  Possibly done under duress, then passed out the back door in the dead of night wrapped in a brown paper bag...

....along with a complementary 60A chassis fuse.

Ron Toolsie posted:

Richard Dane posted:

Ron Toolsie posted:

...Likewise those rare custom extra length Snaics that they made with great reluctance. Or was this just an urban myth?

I've heard of such things - up to 3m!  Possibly done under duress, then passed out the back door in the dead of night wrapped in a brown paper bag...

....along with a complementary 60A chassis fuse.

Is that a 2 inch or 3 inch nail?

Nothing as crude as a nail...many years ago (1984) I 'fixed' the breaker box that had old fashioned pig-tail fuse wire with half a meter of NACA 4. The 135s (one of the very first ones ever made) loved it ;=)

Now now, you two...

docmark posted:

Nope, not a shoplifter - the pocket is just big enough to accommodate a cell phone.  Well, unless I'm thinking of lifting small high end goods like watches perhaps.  Or cell phones.  And I don't have an intolerance to EMR - I'm not convinced that such a malady really exists.  No pacemaker either.  I just found these pockets after I had purchased the jackets, when I noticed tags attached to the zippers.  They're made in Italy - maybe the Italians are onto something they're not talking about.

Go on then, contact the shop or Italian manufacturer and ask what it's all about. Wonder if it is to in any way shield the heart. The Italians can be a strange lot. Had a friend with an Italian husband another with an Italian boyfriend. The girls knew each other and would talk rolling their eyes at their partners' hypochondria - apparently an Italian national trait (they both live a number of years in Italy)

Yeah the intolerance has no scientific basis. It's a great part of the story line in Better Call Saul the Breaking Bad sequel. The sufferer is sympathetically portrayed though it's clear other issues are at root in his illness.

Innocent Bystander posted:

Atvtge price you mention, it surely is worth a punt and listen?

I dont have faith Id hear any tiny improvement. And I think if I did it might be cos of my expectation (bias)

But it's like the philosophy of the Sky cycling team. Many, many marginal improvements, like a redesign of the velcro flap on a cycling shoe giving a 1% improvement on the aerodynamics of the shoe. If you do this enough times there is a very meaningful overall gain. (And for Sky (ab)using allowable prescription drugs.)

Same in my opinion with hifi. Better actual units (preamp etc) produce obvious SQ improvement, But when it comes to things like better wires and a lot of set up tweaks I'm sceptical of many claims of transformitive improvement and reckon few are easily noticeable, The Isoacoustics Gaia speaker feet I've added have been such an exception - great product.

gramophone posted:

Innocent Bystander posted:

Atvtge price you mention, it surely is worth a punt and listen?

I dont have faith Id hear any tiny improvement. And I think if I did it might be cos of my expectation (bias)

But it's like the philosophy of the Sky cycling team. Many, many marginal improvements, like a redesign of the velcro flap on a cycling shoe giving a 1% improvement on the aerodynamics of the shoe. If you do this enough times there is a very meaningful overall gain. (And for Sky (ab)using allowable prescription drugs.)

Same in my opinion with hifi. Better actual units (preamp etc) produce obvious SQ improvement, But when it comes to things like better wires and a lot of set up tweaks I'm sceptical of many claims of transformitive improvement and reckon few are easily noticeable, The Isoacoustics Gaia speaker feet I've added have been such an exception - great product.

I’m with you generally on the last paragraph, however it seems that you have concern your ‘brawn and brains’ are closer to each other than ideal, sufficiently to not only ponder over the shield but also to start this thread. That concern will remain if you don’t do anything about it, hence my suggestion that in hifi terms the cost is trivial so worth a punt. Alternatively, try moving the PSs out of the rack completely, to the limit of the burbsys, supporting them on something as solidly as you can, and see if you hear a difference - if sound quality improves, try the shield, if it doesn’t (or worsens), don’t bother.

Innocent By

I’m with you generally on the last paragraph, however it seems that you have concern your ‘brawn and brains’ are closer to each other than ideal, sufficiently to not only ponder over the shield but also to start this thread. That concern will remain if you don’t do anything about it, hence my suggestion that in hifi terms the cost is trivial so worth a punt. Alternatively, try moving the PSs out of the rack completely, to the limit of the burbsys, supporting them on something as solidly as you can, and see if you hear a difference - if sound quality improves, try the shield, if it doesn’t (or worsens), don’t bother.

Agreed, cheap and easy the sheet. But what Richard Dane said (2nd post) was troubling and puzzling. Im gonna search here as well as outside this forum to get some answers.

About a constant niggle if I don't sort it out. At the moment my head's spinning with good and bad questions and good and bad answers both from me and elsewhere (I think there are loads of dubious claims in the hifi world, as do I'm sure many others). Presently been v active upgrading system from a Uniti Star to a new one which in a few weeks will be completed with the NDX2 when the units start rolling out from Salisbury. Bought several fairly new ex demo units to make up the system in the last month or so along with various accessories and even had installed a dedicated power circuit. So head's been buzzing with all this. Which has been interesting. But I think I'll settle back to enjoy it all once the last piece arrives and draw a line. It's one thing questioning options as you're deciding, its somewhat negative questioning your choices after theyve been made. However the final outcome of my system buying decisions pans out the set up's gonna be enjoyed and not questioned. At least for a good few years.

So any niggle in my mind over the B vs B separation will either be resolved soon with some new accessory or tweak or will be determinedly put to one side and forgotten about. The issue can play on me now (and these kind of things are interesting) but all this kind of thing will be put to bed once the last piece arrives.

You suggest moving out the PSs from the rack  (so not so much the power amp?).  Cos doing this would stand out a bit too much in the room for my taste I dont think I'll do this. But I may well take your advice which I'll follow in a less radical way - putting the PA above the PSs on the lower three shelves. Do you know if the size of the unit's transformer is the overriding issue? Ive got 555 and supercap PSs and a 250 PA so perhaps I should arrange them by this criterion.

The moving of PSs was just for a listen, so too much in room shouldn’t be a consideration.

If having two racks, which is the best option, is out of the question, I’d set it up with - from the top - 252, NDX, gap, 250, Supercap, 555. That should keep all the burndies off the floor and give space between the powered and unpowered components. Keep the burndies off the floor and not touching the stand, wall, or each other. Then keep the interconnects and speaker wires away from the burndies. These tweaks are all free and are well worth doing.