Is aluminium just as bad as steel for hi-fi equipment sleeves?

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when a taxi goes by the house, I sometimes get breakthrough of its transmitter (ie. radio interference).

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Alex

Same thing happens when you remove the cover of a napsc. I don't think it's the ferrous thing because simply leaving the screws barely threaded with cover in place causes an improvement in sound. If it wasn't for having to place the napsc on the floor (prime target for a dog-lick...once anyway) , I'd leave it sans cover permanently.

dave

Tom Evans The Groove has a plastic case, and I have never heard RFI breakthrough with that.

Perhaps we should go back to wooden cases ?

David

...and wooden circuit boards ;-)

dave

Alex

ps Step 1: remove the Naim feet + screws and replace with three pulsar points.

The material has eddy-currents induced into it, making it behave in a magnetic fashion all the time an AC signal is nearby.

It's the same principle a car speedo works on (mechanical type).

My reservation is that any benefits obtained by removing the 'magnetic' materials could be wiped out by totally absent EMI shielding. The circuitry can be designed to reduce the effect of external RF, but that may have deleterious effects in itself.

The proof will be in the listening though - would you like me to bring some transmitters with me on Sunday too

Andy.

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Denis Morecroft's ideas relate to the fact that even non-magnetic materials (such as aluminium) can display magnetic properties when exposed to an AC field.

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I read an interview with Richard Dunn from NVA years ago, he had some really interesting views here. He firmly believed that any metal that was not totally necessary to producing sound should be removed from the amp. I think he was possibly the first to really grasp the adverse effect of metal, and this stemmed from the fact that he thought his early amps worked far better as boards lying on the test bench than as finished and cased products. Experimentation led him to glued perspex / plastic cases as he even found the adverse effect of the case screws was noticeable.

Tony.

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Tony:
I read an interview with Richard Dunn from NVA years ago, he had some really interesting views here.

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Ithink that interview is still available. NVA appear still to have been trading, at least until recently. I remember hearing an NVA amp of some sort with a Linn and some Kans years ago, and I remember thinking it sounded fabulous. Certainly the "Black Box" range (and the CD players) were also some of the best looking audio ever marketed, IMHO. Not sure about the "Statement" stuff...

More info (including that interview) here.

Best;

Mark

(an imperfect
forum environment is
better than none)

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Ithink that interview is still available. NVA appear still to have been trading, at least until recently.

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Great to read Richard Dunn's viewpoint again, the man makes a great deal of sense. how's this for a great quote for electronic design:

" The basic concept is not to use anything that is not needed. There is no such thing as a good component. All components are bad, but some are less bad than others. There is only one good thing and that is nothing. The way I design my products is to use the simplest circuit possible, and make the most of it, and make a good product that the customer can buy at a reasonable price. "

I hope that this sites existence proves that NVA are now alive and well, especially as there is a very new looking CD player listed (I had a nasty feeling they had gone down the pan, there was a period a couple of years ago when the Statement range was being flogged off through the hi-fi rags for well less than half price.).

NVA had / have some truly excellent designs and were always very well respected by those who like their hi-fi to make music. Quality stuff indeed.

Tony.

"The basic concept is not to use anything that is not needed." What a valueless, facile statement! This is the sort of thing people say when they aren't good at system design.

I had a look at the NVA site. I notice that they make a marketing play of using military grade components. Well that does makes sense doesn't it? Are we to feel assured in our knowledge that Army Procurement Divisions are staffed by audiophiles who's mission is to buy the best sounding warfare materials? Perhaps we can facilitate the capture of the Taleban's troops by stunning them into blissful paralysis with a blast of audiophile Vivaldi. That is unless they are already deaf from being bombed with audio grade components.

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I hope that this sites existence proves that NVA are now alive and well, especially as there is a very new looking CD player listed (I had a nasty feeling they had gone down the pan, there was a period a couple of years ago when the Statement range was being flogged off through the hi-fi rags for well less than half price.).

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I think they are. I bought an AP10P (one input) jobby from them a few years ago for a bedroom system. I drove to the factory which was then in Buntingford to pick it up. There was quite a bit of finished top of the range kit lying about. I chatted to Richard Dunn who said that the majority of their stuff at that time was destined for the US. He felt the UK magazines were locking NVA out.

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I can't resist Top Cat's priceless quote that dnm looks 'like a lunch box with cooker knobs on'

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Yeah, but that hasn't stopped me ordering one. As far as hifi components that I've ever bought go, this one has the least 'hifi jewellery' appeal of all - and I stand by the quote!

Andrew wrote:

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I believe what Denis Morecroft has to say on this matter. His amps sound INCREDIBLY dynamic (way more than Naim does), but also incredibly ugly. Difficult to describe but I couldn't live with that sound.

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They are dynamic, although I have only ever heard DNM amps in the context of a system similar to mine. Actually, dynamic wasn't the first word that came to mind. I thought of 'organic' first and foremost when I substituted a DNM preamp in place of my little Crimson unit. The rest of the system goes like: Crimson 640D 200w monoblocks, Clearaudio Evolution/Tangent/Sigma Gold MC, Neat Petite III/Gravitas speakers. In the context of this system the improvements I found were of a sort of layering of sound that I hadn't really heard in any other system before. The 640Ds are incredibly fast and dynamic, powerful amps (especially considering their size) but I was only getting a part of their potential performance with the cheaper Crimson preamp. There is definitely a synergy in these DNM amps, but I don't necessarily buy into the non-ferrous ideal (after all, I surrounded the whole lot with a couple of hundred pounds of angle iron

My own take on it is that the benefits of the DNM amps is more down to their circuit simplicity and custom slit-foil capacitors. I think the sound runs orthogonal to Naim in some ways, but in a no less valid way. I'm awaiting my preamp arriving from Switzerland as I write this, dealing with an eclectic little firm like DNM/Reson is an exercise in patience

Ugliness? Damn tootin'! Fisher Price meets Naim is the best way to describe them other than my other quote!

But the sound is divine... interested to hear what you found irksome with the sound, though...

Anyone interested in hearing my system would always be welcome to drop by if they are in the area...

John

I was told that the power amps are completely without protection, and can be overdriven quite easily.

They once shorted the ends of a cable whilst unplugging from the speakers and flames came out of the back of the amp. Believe this if you will.

Still, they do sound excellent.

cheers, Martin