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PostPosted: Thu Dec 15, 2011 11:19 pm 
Retro Guru
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Joined: Thu Oct 13, 2011 9:30 am
Posts: 958
Location: Malvern
No?

OK, it's an NVA, and it's utter junk built on utter junk principles. It keeps blowing up because it has no stability as ' that destroys sound quality'

OK, so it's better to allow it to oscillate at RF - which a non-shielding plastic case helps with no end!

The boards are glued in, because screws ruin sound quality (!) (this also means boards have to be replaced every time it cooks itself as the glue coats the underside of the PCB - handy eh?)

Look at the earthing strategy? How many earth loops do you want? This is the reason the case is plastic - apparently. To prevent eddy currents in the casework. If the earthing was designed properly, there wouldn't BE any currents flowing in the casework!

It's not mine I hasten to add - I prefer physics and science to claptrap and fairy tales. :lol:


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PostPosted: Sat Dec 17, 2011 10:13 am 
Old School Grand Master
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Joined: Sun Jan 06, 2008 2:36 pm
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NVA has excellent feedback in his ebay shop........perhaps you have a duff one........isn't it about sound quality at the end of the day ?


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PostPosted: Sat Dec 17, 2011 10:17 am 
Old School Grand Master
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3,080 people left him with his 100 % feedback, he must be doing something right :D

I know NVA warns it's amp customers that they must use solid core, not twisted speaker cables as this will damage it's amplifiers (something to do with resistance).......any solid core not just the ones they sell !


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PostPosted: Sat Dec 17, 2011 11:11 am 
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Quote from the site ''Litz or Goetz cable or other designs of high capacitance cable will damage the amplifier.''


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PostPosted: Sat Dec 17, 2011 4:18 pm 
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Joined: Thu Oct 13, 2011 9:30 am
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Location: Malvern
I don't have one. It belongs to a friend. Yes it's about sound quality, but that can come through sensible design as well as the lash up that is the NVA. (Personally, I don't think it gets close to my Alpha 9 as far as sound quality)

The NVA is badly designed IMO. There is no HF stability, it is not properly stable with any speaker cable, not just specific capacitive values, therefore there is always the chance of a 'fry up' for want of a better word. Just touching the speaker cables could be enough to induce sufficient RF current to cause it to oscillate, and as there is no protection either (more 'bad for sound quality' nonsense) there is always the chance that it could take out your speakers before it cooks itself.

Personally, I wouldn't own one - and I do understand this stuff on a technical level, rather than just being blessed with golden ears (if such a thing is any more than plain old hifi 'expert' twaddle)

I don't believe good feedback (no pun intended) on eBay is necessarily an indication of a great product either. As I said earlier, serious hifi folk can be as gullible as hell!

But then, you pays your money... :wink:


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PostPosted: Sat Dec 17, 2011 7:55 pm 
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I think i would always prefer some kind of protection circuit myself.


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PostPosted: Sat Dec 17, 2011 8:06 pm 
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Yes, me too.

It's all well and good to suggest that a protection circuit impacts sound quality, and yes, a badly designed one using cheap components could do, but to eschew any protection, and then intentionally build an amplifier with no mitigation against RF oscillation is just dumb - and will only end in tears.

A decent protection circuit need not introduce any noticeable degradation - a communications quality relay contact in series with the signal for instance. Better I think to design the output stages with inherent stability though - it's only a very low value air cored inductor to neutralise the capacitive effects of cables (and speaker some crossovers!).

I wouldn't mind betting that you could put an inductor in series with the output of that NVA, and no-one would hear any difference.


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PostPosted: Sun Dec 18, 2011 10:10 pm 
King of the Skip Monkeys
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Location: Moomin Valley
I dont know about 'Golden ears', however, I was trained by some very knowledgeable people and taught to use some quality equipment. My 'ears' still listen for certain characteristics when testing audio systems - it can ruin music when its not been mastered very well or the equipment is flawed.

I still have yet to learn how an amplifier works! To be honest, I'm not that bothered by it. Either it sounds right or it doesnt, and many sound terrible.

I worked with speakers, DAB and a bit of video processing. I left amplifier design to the guys that had been in the game 20, 30 years or more.

As for Peter Belt -absolute fruitcake. We voided the odd warranty when shown some pictures of our £2500 processors covered in foil! Same with power cables and other mad stuff.


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PostPosted: Sun Dec 18, 2011 10:21 pm 
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Location: Malvern
I've always tried to follow the philosophy that amplification should do nothing but that. Signal out should be the same as signal in but bigger. End of. Happily there are well defined theories that govern how that works - or doesn't work. Some loons ignore said theories and invent their own in order to fleece the wealthy consumer. Well, that's the only reason I can think of as to why they'd flout the science in favour of the tooth fairy.

Glad to hear I'm not the only one to see through Belt's lunacy. Do you remember his Linn PSU mod, which left 240VAC mains exposed to enthusiastic fingers (and perhaps children of hifi enthusiasts fingers?) which caused a bit of a storm and may have led to the end of HiFi Answers as it was?


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PostPosted: Sun Dec 18, 2011 10:30 pm 
King of the Skip Monkeys
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Joined: Wed Nov 07, 2007 4:34 pm
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Location: Moomin Valley
One of the people I use to hassle all the time was Douglas Self, nice guy if you didnt prod him too much.

Russ Andrews is another twonk:

Quote:
Russ Andrews PowerKord-8

"...It let our kit produce sharp, detailed images. Colour was natural with convincing skin tones, while sonically this mains lead gave our setup a wide, revealing sound ... "
from £86


Talking of cables, I still have about £5k retail worth of S-Video cable in the loft, should really do something with that I suppose.


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