NVA amps

I'm perfectly willing to accept that taking an entire amp including the PSU from a plastic or wood case and puting it into a steel case might make it sound a little different.

But screws???

Oh come on folks :banghead:

 

You can hear the effect a magnetic screw has in a plug on a system.

 

That's bound to wind him up even more!

 

mmm.. I think a lot of people could hear the effect a bee farting in New Zealand has on their system if they were told they should be able to :meister:

 

:ffrc: :ffrc: :ffrc:

This thread just gets better and better...........

 

lol, then you need your ears clearing out!

 

Aha! more mechanical capacitors, semi fluid ones

Richard

 

There are many other oddities. A metal case will obviously conduct. I plastic case will obviously not, but a plastic (especially Persex / acrylic) case will hold a static charge. What is the significance of this and how do static charges effect audio signals in close proximity. How does a static charge propogate and how do you remove it. It is not the same as an electrical current, induced or otherwise. It has different properties, but one can influence the other. Also a screwed plastic case (even plastic screws) has different charge properties to a glued case. All explored in our original case explorations work, but for you I am sure just a complete waste of time and worthless of comment.

Well your the loser not me A closed mind is a serious dissability.

Richard

 

Richard, having a closed mind ( a charge I refute) and the good sense and ability to cut through hot air and cobblers, imaginary differences and belief in unproven theories is entirely different.

The case may effect the sound, if you change the whole thing from steel to wood etc, I have not stated otherwise, but a few screws will not. The effects of the case are due just as much to screening than to any of your theories. RF entering the circuit can be a real pain, indeed it made your Phono 1 utterly useless in my system due to a fantastic ability to relay the converstaions in every passing taxi cab, not to mention the many unwanted radio stations I was introduced to.

My own amps sit in - horror of horrors - heavy steel cases. Many from this BB and PFM have heard them and I've yet to hear any negative comments. Perhaps they were all just being nice or perhaps any adverse case effects were not important enough to hear.

Many on this board greatly enjoy the TVC magnetic pre amps, which of course use double screened transformers in metal cases. Are they deaf?

 

In for a penny, in for a pound

 

The closed mind is completely apparent no matter how you deny it. You have done no work on cases, I have and yet you insult my work with no knowledge, AND as well for the upteenth time yet again completely misinterpret what is relayed to you. Where have I critised your amps or any other amps. How do you know they would not perform better with some of this work behind them, you don't. You are predudiced and your mind is closed as you insult on principle from a position of complete lack of knowledge on the subject being explored.

There are many many parameter involved in amplifier design, we are exploring in this discussion just *one* of them. That is not *the* most important parameter, but *one* of them in my experience. I think 30 years of work on the subject would at least deserve some respect from a prat who hasn't even spent one minute on the exploration of this design characteristic. But who has continually insulted and played mind games. To what purpose? who are you trying to impress? or is your self esteem and arrogance so dominant you don't recognise it.

I welcome an explanation of your design experience in coming to your dismissive conclusions. I expect discussion lists to be a little like this, but this is crazy! Design an amplifier for me and prove me wrong, as I can easily prove me right. You only have to listen to a 1986 NVA v 2006 NVA and the only thing stopping the obvious would be a serious case of cloth ears. The circuit is the same, the voltages are the same, the objective design parameters the same. All you have in exchange for these facts is insults, predudice and a closed mind.

Richard

 

Sure, but its pointless if there is no audible effect. I don't believe there is.

 

Actually screws can effect the sound .....I screwed a horn speaker cabinet together ..then glued it only the difference was not subtle. this may have had nothing to do with the distortions of magnetic fields and more to do with a more rigid construction. But the spound was far more open and natural after screw removal.

As an aside if you place an object in a magnetic field it will distort the field.....so I have no doubt that steel screws will play old harry in the same way.

 

Very interesting bluster Richard.

I'm listening to the R3 proms as I type this on an Accuphase tuner encased in a steel case. I've just removed it - absolutely no difference, nothing. It is currently playing through a Cyrus 2 amp (not the usual amp) and that also sounds the same clothed or unclothed.

I've worked on and repaired many amps over the years which means testing and listening with the cover removed. Never any audible differences apart from the odd bit of RF pickup.

I don't doubt your ability to build good amps but there is no need to dress up your products with this nonesense. By your own admission you use simple circuits and you execute them well enough. But believing that changing or removing screws from a case will improve the sound of your products puts you into the same catagory as the magicians who constantly invent the perfect cable year after afer year.

Doesn't wash with me Richard.

BTW please stop refering to your opinions as 'facts' - they are not.

I think you need to look a little closer to home there Richard.

<edited further to Mr Dunn's threat to 'pursue me' >

 

They are facts and can be proved as I stated in my last post. If other equipment doesn't benefit from this treatment is not my fault. If a window is dirty it matter not how many screws there are in the frame, it remains dirty.

You are still talking from position of ignorance as I *only* refer to nva amplifiers. I could not care a tiny bit less if other products gain or lose. I do not experiment with other manufacturers product. Do not challenge my ability to understand my product or my motives because am getting pretty close to being litigious over your behaviour. You caste aspersions on my reasons for my design criteria once more and and you will feel the weight of the toys coming out of the pram. Who the bloody hell do you think you are claiming my design criteria are deliberately false or that it is some form of window dressing. This is a public forum and I will pursue you if you continue.

Richard

 

That is completely contrary to my experience – the only amp I’ve tried this with was a Naim 32.5 and it sounds noticeably different to my ears with the case off.

You need to loose those ferrous Sound Org stands and then you will start to hear these things

I’m not saying it is mission critical, there is much great hi-fi with ferrous casing (Leaks, Quad IIs, your Accuphase etc) but the phenomenon Richard describes certainly exists. I’ve heard it.

Tony.

 

:MILD:

Ok Richard, you win.

I'll simply let other members of this BB come to their own conclusions on the above statament and let it rest there.

 

That's a fair point Tony, but it would be good to have an open discussion as to why you might hear those effects. I've suggested that it could just as likely be due to RFI getting in - the differences heard might not necessarily be for the better.
Take the steel screws from your Denon Tuner and tell me, hand on heart, that you can hear a difference

 

I won’t hear anything as it has a steel chassis and is therefore utterly irrelevant – the steel chassis will be holding it back far more than a few screws ever can. As I said earlier this doesn’t make it a bad tuner at all, it’s actually a seriously good one. The point you really start to hear this stuff is with things like say a DNM or a Tom Evans, i.e. things that have been designed with an understanding of how materials interact (they both use plastic / Perspex cases). Place them on a metal stand and hear everything kind of ‘go off’ a bit. The Nac 32.5 is pretty easy to hear too as it is aluminium and doesn’t have a transformer or other large ferrous items nearby. Try it, but do it on a decent stand, i.e. not a metal one.

To me this stuff definitely exists, I have proven it to myself on many occasions (and yes, on occasion in blind test environments), but it is not the be all and end all. It is not mission critical. I have things in my system that are ferrous (tuner, valve amp), but I acknowledge the fact and keep them as separate as I can from other things designed in a different way. It is all to easy to get carried away with this stuff, but it is also worth understanding as much as possible about how things interact as it can be a free upgrade or two.

Tony.

 

Agreed, But aren't you curious to look at why there might be a difference ? I wasn't joking when I said that removing the case from the Accuphase made no difference. In the case of my pre amp it is unusable without it's steel case and sounds worse - but with good reason- the case greatly reduces the intrusion of RFI into the circuit.
The DNM comparison is interesting as his pre amp (and I beleiive hs power amps) are pretty bandwidth limited and less likely to suffer RFI problems.

Another phono stage I used a few years ago, from a designer firmly in the non ferrous camp, was so prone to RFI that it was laughable. Ultra wideband, high gain curcuit in a largely metal free case....... you see my point?
There are forces at work here, perfectly easy to measure and explain forces and there are others which require a degree of belief
IMO, the screw issue goes firmly into the belief camp.

I think this is a good discussion and well worth having but preferably not now within this NVA thread given Richard's recent threat. It's also a little off topic by now