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Post by jazzbones on Feb 2, 2015 16:15:45 GMT
My own mono power amp cases and that of my control amp are of the extruded aliminium type but I have seen amps using plastic/acrylic such as Dennis Morecrofts of the 80s and more recently NVA, I am aware that a prominent personality on another forum has a copper glad amp, and some early Creek 4040 (have one in the office) where encased in wood composite. Then, of course there is the all metal sheeting case. To date I have never seen one encased in stone, slate or granite but the audio world is full of surprises so there is probably one around somewhere. The Big Question is: What do these various material contribute to the performance of an amp and do audiophiles have a preference and why? What is behind the thinking of the amp designer?
Incidentally, my amps have a composite of cork and granite in the form of a Morrison's slab strategically atop the amp for dampening purpose.
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Post by MikeMusic on Feb 2, 2015 17:09:26 GMT
I bet this is mostly the look.
In some cases (!) a lower cost.
Martin T, I and likely others have recently discovered granite placemats on the top of kit, including Pre and Power amps makes a marked difference and improvement to the sound
The next logical stage for the brave has to be fiddling around and inside the case
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Post by ChrisB on Feb 2, 2015 19:08:40 GMT
The DNM stuff was like that because of a desire to remove as much metal as possible from the entire unit. Cases from acrylic and fastenings from (I think) nylon. I think it's meant to reduce the opportunity of the signal producing eddy currents in the unit and thus creating distortion in the output (or something like that). I don't really understand how, but I know eddy currents will effect even non-ferrous metals. I've watched eddy current separators being used to sift non-ferrous metals out of shredded wood and also in a waste recycling plant to do the same thing. The NVA approach may be for the same reasons, I don't know, but the design page of the website does refer to the use of non-magnetic acrylic casework and the elimination of steel screws in favour of glue in order to avoid 'magnetic contamination'. Also, there are no metallic heatsinks either, so I rather think there's more to it than just aesthetics as Mike suggests. I also vaguely remember a massive corian cased preamp of US origin in the late 80s or early 90s. |
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Post by Mr Whippy on Feb 3, 2015 21:08:32 GMT
The DNM stuff was like that because of a desire to remove as much metal as possible from the entire unit. Cases from acrylic and fastenings from (I think) nylon. I think it's meant to reduce the opportunity of the signal producing eddy currents in the unit and thus creating distortion in the output (or something like that). I don't really understand how, but I know eddy currents will effect even non-ferrous metals. I've watched eddy current separators being used to sift non-ferrous metals out of shredded wood and also in a waste recycling plant to do the same thing. The NVA approach may be for the same reasons, I don't know, but the design page of the website does refer to the use of non-magnetic acrylic casework and the elimination of steel screws in favour of glue in order to avoid 'magnetic contamination'. Also, there are no metallic heatsinks either, so I rather think there's more to it than just aesthetics as Mike suggests. I also vaguely remember a massive corian cased preamp of US origin in the late 80s or early 90s. That Eddy Currents gets the blame for an awful lot… |
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Post by MartinT on Feb 8, 2015 13:27:11 GMT
The equipment I favour nearly all consists of thick sheet or extruded aluminium construction, and there's a lot to be said for that. It offers shielding and non-magnetic characteristics. Granite makes for great further damping.
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Post by istari_knight on Feb 8, 2015 16:39:57 GMT
It certainly inspires confidence & pride of ownership when something is machined from a billet or indeed extruded as you say Martin. Having made DIY amps myself using wood/acrylic/steel/aluminium for the cases I've concluded they have very little affect on the sound quality produced... Heck, at one point I had a completely exposed breadboarded preamp sitting on a plastic DVD case on the floor 10" away from a 12" bass driver rattling the bejesus out of it with no audible consequence... So I don't believe vibration makes much of a difference. Cant really comment on old Eddy other than I've yet to encounter a design, metal or otherwise where he was an issue  So yeah, IMO its entirely down to manufacturers production costs, perceived quality/value by the customer & a little bit of marketing BS never hurt anyone [not]. |
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Post by Sovereign on Feb 8, 2015 16:48:06 GMT
I've had many NVA amps, really like the look, very smart
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Post by MartinT on Feb 8, 2015 17:23:25 GMT
I've never seen one in the flesh, Sov. Are they essentially acrylic in construction, like the DNM amps?
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Post by jammy on Feb 8, 2015 17:31:12 GMT
I've never seen one in the flesh, Sov. Are they essentially acrylic in construction, like the DNM amps? I like the look of em......Understated and Black and ermmmm ........Shiney.  www.nvahifi.co.uk/preamplifiers/ |
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Post by MartinT on Feb 8, 2015 17:36:52 GMT
I can't see the material used in the blurb but it certainly looks like nicely finished acrylic.
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Post by chukka on Feb 10, 2015 21:25:07 GMT
The NVA approach may be for the same reasons, I don't know, but the design page of the website does refer to the use of non-magnetic acrylic casework and the elimination of steel screws in favour of glue in order to avoid 'magnetic contamination'. Also, there are no metallic heatsinks either, so I rather think there's more to it than just aesthetics as Mike suggests. no metallic heat sinks  maybe non magnetic ?? anyhow this all sound like a bunch of BS and boutique talk to the gullible... the only reason I can see is so nobody sticks their noses to deep into them  |
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Post by guy on Mar 18, 2015 19:25:02 GMT
no metallic heat sinks maybe non magnetic ?? anyhow this all sound like a bunch of BS and boutique talk to the gullible... the only reason I can see is so nobody sticks their noses to deep into them If you really wanted to have a look inside one surely it wouldn't be beyond your expertise to open one up and glue back together once you had stuck your nose in to it. Mr Dunn managed to open up my NVA phono 2, adapt from MC to MM sensitivity and reseal in about half an hour. |
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Post by Deleted on Mar 18, 2015 20:41:02 GMT
Having had lots of NVA amps from 1986 onwards, I can vouch for the acrylic casework. The acrylic cased amps simply sound better and it's not subtle. They also look and feel very sumptuous too. If I was making amps, I'd use acrylic although from what I have seen, it's not cheap. I have also seen inside most of the amps I've owned including NVA. It's a doodle to take the top off one of their products because they are designed that way. A different adhesive is used.
Incidentally all amps from every era have been well built. The wiring isn't in a loom like Naim but this is deliberate because the designer be'ieves the wires "talk"'to each other if grouped that way. If you are OCD about spaced wiring, just leave the top on.
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maybe non magnetic ?? anyhow this all sound like a bunch of BS and boutique talk to the gullible... the only reason I can see is so nobody sticks their noses to deep into them 
