NVA components

I wonder if anyone can advise me on these products. I remember years ago listening to a system comprising NVA and , I think, LS35a speakers( cant remember which T/T) and was most impressed. I found very dealers who sold the stuff and gave up but I now see its made a bit of a comeback in Ebay of all places. Anyway I am kind of interested but as they obviously dont offer any kind of demos, I'm having to gather other people's opinions in various forums .One thing i picked up is that the manufacturer heavily recommends the use of his own cables and i am wondering why?What so special about them? Apparently they need to be low capacitance( whatever that means - sorry but I am not technical) and preferably solid core.His speaker cable consists of 7 solid core strands which kind of confused me as i thought solid core meant just one thick strand as in mains cable. anyway could anyone please advise me. Thanks
One thing - I did email the manufacturer but he was rather economical with is advice saying that I could try it and if I wasnt happy I could get a full refund. Not much of a feedback really

 

It's fair enough, if you don't like it send it back and get your money back. How many hi-fi shops will let you do that?

 

Most of the ones I know will give me a home demo. Most of them in fact without coughing up a penny.

 

yes i wasnt question the rights and wrongs of that but was looking for some advice but got precious little, there was some bumph on the ebay site which kindof ( I think) explained things but me not being technical meant I could understand little.

all this stuff :

What determines the way that cables affect system performance to a far greater degree is the output impedance of an amplifier. The question of cable inductance, capacitance and resistance has to be considered as an integral part of the amplifier/cable/loudspeaker interfacing equation. Amplifiers such as NVA's, Naim's and Exposure's which do no have a Zobell network on the output, are sensitive to the effects of capacitance and inductance. Transistor amplifiers with Zobell networks or output filtering and valve amplifiers with transformer coupling on their outputs are not so sensitive. If an amplifier has negligible output impedance (ie the damping factor is high), the effect of relatively high cable resistance is minimal. Our LS1 cable is a fairly high resistance cable, but our amplifiers have a 0.0065 ohm output impedance, so there are no ill effects.

Cable directionality is a audible phenomenon. Indeed cable performance can vary with even more obscure factors than this. I have found with solid core cable it is possible to create directionality over a period of time. It's as if the cable beds-in when used aligned one way. If you then reverse one of the cables it can sound worse. But if left, it will bed-in once more over a period of time.

I agree that the cable dielectric is more important than the conductor purity. However if you coat a copper cable in silver, the change will affect performance as much as any change in dielectric material. The dielectric is know to affect cable capacitance more than any other factor with the exception of using Litz construction. Output transformers and Zobell networks hide the deficiencies of cables. So the danger is the wrong cable solution can be prescribed. High capacitance cables apply a cure to the bad audible effects of Zobell networks and output transformers, but as in medicine, it would be much preferable to not have the condition in the first place!

 

Hi Tootlepip,

Some amps like NVA have no filtering or compensation networks in the output stages. (eg Zobel networks or inductors) This means they can be fussy about the type of cable used. Cables like Litz style or goertz cable have high capacitance. This can make certain amps unstable at high frequencies. NVA cables have low capacitance.

A thick solid core cable will be hard to bend so the use of a few smaller cores would improve this.

Try in your system is the only way you will know if you like them. NVA are selling mail order and not by a shop network. A few companies do this now. They offer money back if not satisfied.

SCIDB

 

so what determines a cable's capacitance? I've heard plaitted/twisted Cat5 types are bad. But what are the criteria for making a low cap speaker cable that could be used with NVA?

 

As a general rule, thinner conductors have lower capacitance but higher resistance and vice versa.

 

Hi Simon,

The closer the conductors are together the higher the capacitance, lower the inductance. The further they are spaced the lower the capacitance, the higher they inductance. Resistance is determined by the material and length and area of the conductor.

Twisting a cable will increase the capacitance and lower the inductance.

SCIDB

 

So, how would yo ugo about spacing the separate strands in a speaker cable?
And what harm does inductance do?

 

You don't, stranded conductor acts much the same as a solid-core conductor provided the strands are not individually insulated. SCIDB was referring to the spacing and twisting of the + and - phase of the speaker wire, where the induced field of each cable will cancel out if they are twisted tightly.

So if you want low capacitance you want thin conductors that are spaced from each other (not twisted). But you will get high resistance and inductance.

 

Hi,


By having individual insulated conductors, this will act as separating the conductors. It can reduce inductatance. But to work well the individual insulated conductors need to be quite well separated. The way a number of companies do it is to coat the strands in a good dielectric such as teflon and have a few strands.

SCIDB

 

what's thin, 0.7mm?

So you could use cat5 strands (the PTFE coated one), after removing them from the outer sleeve that is? Would the spacing cause by the insulation be enough, as in, can you just bunch them all together and put a sleeve over them?

 

Cat5 is very similar to NVA LS1 cable in gemoetry though the metals used are different.

I asked for some 'clarification' regarding the use of cables with NVA equipment (including LS1 which is supplied as mono untwisted lengths) - clarification was not forthcoming from the designer at that time, so best of luck to you mate.

The amps though are rather good but you may find benefit in using a larger model than you first expect. The dsigner believes in reducing he amount of metal used near the circuits to a minimum so you may find the smaller amps will run hot if run near their limit for long periods. Probably best to stick with the NVA passive pre amps as the use of 'foreign' units carry the same health warning as with Naim amps - for good reason.

 

Hi,

You can do that but you will still have high capacitance. again this may not be a problem with most amps. If you are using amps like NVA, I would avoid cables like this. Amps without safety networks could oscillate or blow up!

Dean

 

Hi,

Sounds like some simple 2 core, thin, mains or lighting cable will do the job. Go to B&Q and look for the thinnest conductor diameter 2 core cable. Solid core is preferable IMO since it stays put but not essential.

 

Hi Rob,

Cat5 is twisted together. NVA is may not be. I have not seen inside the NVA so I don't fully know.

SCIDB

 

Incidentally,and sorry to point out the obvious, distance selling regulations, if you buy mail order - (not sure if you have to use a credit card (? but I do anyway) - anyway, they HAVE to give a refund within 14 days if you send back, they have no choice.

You don't have to give any reason for sending it back under the legislation.

 

but won't thin 2 core have a really high resistance?

What's the difference in using a few separate (untwisted) strands of cat5 PTFE (teflen?) coated wire, and how the cable manufacturers do it?

Sorry for not getting it, i've got a block going on

 

Not really, if it is rated with high enough current handling for mains cable it is enough for speakers and the resistance will be negligible. Bedsides, amps like driving in to a load. The worst it will do I think, is to roll off the treble a TINY bit, but for that to happen in the audible range it would have to be some large resistance there.

 

hmm, sounds a good way to go then. Would anywhere have a capacitance meter I could use?
ALso, on his site Richard Dunn says the LS1s are just groups of 7 separate wires in a tube (in bubble wrap or something, doesn't go into detail). Then a completely separate lot for the other terminal. Is this a method for killing capacitance, running completely separate lengths for + and -?