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January 2011 issue - Page 3

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January 2011 issue
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Page 6 - Mac Mini
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CABLE CURSE

I very much enjoy reading Hi-Fi World, which is attractively presented and, for the most part, intelligently written. However, I have become increasingly concerned that some of your reviews, particularly with regard to passive devices such as interconnecting cables, are written in a manner that severely compromises the integrity and reliability of your journal. In the past I’ve simply regarded these as a source of amusement and have let them pass by, but on reading your review of the Furutech Alpha PS-950 mains connector (October 2010, p. 87) I thought it was about time that something should be said.


Surely, you know as well as I do that a mains connector, no matter how elaborately conceived and constructed, can make absolutely no difference to the quality of the sound emanating from an audio system. Is it not apparent to your readers that behind the wall socket, into which this connector is plugged, lies maybe ten or twenty metres of a tatty piece of flat twin plus earth, and that this ridiculously expensive connector forms only a tiny fraction of the total domestic mains distribution network ?


What concerns me is that to suggest that the cable enhances definition, smoothness, openness and speed (whatever these words actually mean) makes a mockery of the entire magazine and, sadly, makes the reviewer look like a fool.

 

Then, and rather more significantly, the question arises as to how seriously the reader should take your reviews of more substantial pieces of equipment. I appreciate that this places you in a difficult position with your advertisers, but could you not be a little more honest with your readership, and in this way gain their respect and credibility? (phrases like more money than sense and laughing all the way to the bank come to mind, but would be discretionary.)


My comments might equally well apply to other interconnects. The sole desirable quality of a loudspeaker lead is that it has low resistance to increase the damping factor. Nothing else really matters. In fact the best loudspeakers leads can be made from a few lengths of insulated copper flex-weave of the type made for transmitting antennas and costing around £2 per metre. And for phono interconnects, a length of 100U satellite coax soldered between a couple of Maplins best phono plugs will outperform anything on the market for a cost of around £8, with negligible capacitance, 100 percent screening and a frequency response extending to GHz. What more can one need?


And, while I’m here, just a final note about your amplifier tests. Virtually all amplifiers nowadays have a flat response over the audible range, and negligible distortion, so such tests tell you little about the real quality of the equipment. What are far more important, but appreciably more difficult to measure, are parameters like intermodulation distortion and, critically, transient response. In the early days, hi-fi magazines used to show square-wave tests, comparing input and output oscillograms at a variety of frequencies, which were far more revealing and not at all difficult implement. Could you not revive this approach?


I do hope, for the sake of the reputation and reliability of your journal, that you take these comments on board. Do publish and reply to this letter if you wish, but I suspect that you won’t.

yours sincerely

Ray Howgego

 

It is seemingly difficult to explain how a short mains connector can affect sound quality when it sits in such a long cable run, but their manufacturers claim they act as filters, removing higher frequency rubbish and I believe I am right in saying that this action has recently been demonstrated to the Advertising Standards Authority in a dispute that has arisen over cable claims. People buy these cables and are very happy with the improvements they hear. We publish these letters regularly.

 

The differences in sound quality between loudspeaker cables and interconnects is accepted by most people, and certainly by us, even if the exact mechanisms are difficult to explain. Sceptics usually say such listeners are deluded so I include one such letter for your perusal.

 

Basic lumped electrical parameters such as resistance and inductance appear to have little to do with it. Materials and dielectrics, as well as screens, appear to be exerting influence, but by what mechanisms we are all unsure. Personally, I suspect materials colouration affects all hi-fi and is an all-pervasive phenomenon, and current density is the stimulus. However, vibration and microphony, and radio pickup may also be influences.

 

Intermodulation distortion is a measure of non-linearity, as is harmonic distortion. They measure the same thing by different means. It’s just that intermodulation distortion comes in a wide variety of forms (second / third order sum and difference etc) and is awkward to measure (we are able to measure all forms). Harmonic distortion gives a single figure of goodness in this area, which is why it is commonly used.

 

Square waves comprise a sine wave at the repetition rate and an associated extended harmonic structure. The shape of the square wave is altered by amplitude and phase changes of its harmonics. A square wave will induce and show ringing of a resonant system but this can usually be seen in the amplitude response. I well recall the square wave tests you talk about and have used them myself, but they reveal no new information over and above what we already publish.

 

Times have moved on and our  instrumentation and understanding of underlying phenomena have also changed. I understand where you are coming from but there are plenty of highly skilled and experienced engineers working in audio who have heard cable differences and accept them.

 

We receive a regular trickle of complaining letters about the cable sound issue, asking or demanding we cease publishing ‘misleading’ information and, for the sake of openness we are happy to publish them. But I’m afraid to say that most people with any experience here accept sound quality differences do exist.  The following view, opposite to yours, is from reader Rudy Deblieck. NK

 

 

So, I get a bit angry with all these people who keep on telling us that the importance of cable quality is overrated, that burning in is nonsense and that it all comes down to ‘psycho-acoustics’. They claim that ‘one simply cannot measure these so called ‘audible differences’...’

 

For crying out loud: I am a solid state physicist myself and as a scientist I know very well how to conduct an experiment, how to compare setups and finally, how to be careful about not drawing conclusions from what has not been measured in the test.

 

The fact is that no measuring device actually measures what the ear-brain combination hears and we should be humble enough to admit that we are not able to do so properly.

Rudy Deblieck

 

 

donald-rumsfeld

 

U.S. Statesman Donald Rumsfeld had a few things to say about what we don't know, David observes!

 

We often get letters from people who 'know' what constitutes a good cable/interconnect and what does not, reducing everything to a question of resistance, capacitance and inductance. Whilst this undeniably plays a vital part, I feel they'd do well to have an understanding of philosophy too, at this point.

 

There are, to quote the unlikely source of Donald Rumsfeld, "known knowns; there are things we know that we know. There are known unknowns; that is to say, there are things that we now know we don’t know. But there are also unknown unknowns; there are things we do not know we don’t know".

 

The assertion that some engineers make is that we can know everything through present knowledge; their contention is that science is now 'finished' and what exists is measurable, and thus if it isn't measureable it doesn't exist.

 

This of course is a logical fallacy; in the 15th century people could not empirically 'prove' that the earth was a globe, yet that did not mean it was not. Likewise, until fairly recently we couldn't detect the existence of Pluto; that did not mean it didn't exist until recently! So I think a degree of perspective is required; good scientists know that there are known unknowns. One of the fascinating aspects of science is finding those unknowns and then finding ways to know them. If ever they need any suggestions, they need look know further than hi-fi, which is full of them!  DP

 

SEARCH FOR COLOUR

Can you suggest any current loudspeakers that give good portrayal of tonal colour, or  ‘good tone’ as it used to be called, and what are you looking to pay nowadays? There are plenty of sharp, detailed speakers out there which can play 100bpm, but their monochrome presentation leaves me cold.  Are paper cones still the way to go if you want a full, colourful sound?

I would be delighted to hear your views on this subject.

cheers,

Jaswant Gill

 

I see it as you see it Jas: too few loudspeakers reproduce a convincing range of tonal colour and the drive toward an enhanced sense of speed, clarity and detail, obtained by boosting treble does not help. Electrostatics from Martin Logan and Kingsound, as well as Quad are strong in this area. I also rather like Spendor’s ep38 polymer cones that have a damped sound lacking zing, found for example is the S8e we use as benchmark loudspeakers.

Pure paper cones are good in some areas but can have ragged upper treble when stiffened. These days manufacturers like Dali use pulp fibre cones that I’ve found surprisingly neutral in themselves and good communicators of tonal colour, but Dali unfortunately like raised treble too. Tannoy are a company that steadfastly refuse to produce a loudspeaker with raised treble and their fibre / polymer cones are pretty good at conveying instrumental colour.

Depressingly, both neutrality and the transmission of tonal colour are properties little considered in modern loudspeakers. NK

 

kingsound-prince-ii

 

Princesound Prince IIs, a full range electrostatic loudspeaker that is smooth and reveals tonal colours.

 

 

 

Hi Jaswant - aside from the Q Acoustics 2050 in the budget region, the most obviously tonally varied speaker I've heard recently is the MyAudio Design My Clapton Grand MM. It's expensive at £3,500 or so, but it has a great tonal palette, and this from paper drivers. The designer pays meticulous attention to passive componentry, wiring and materials technology, and you can hear it! DP

 

CADENZA QUERY

I have been reading your reviews of the various Ortofon Cadenza cartridges, Windfeld and A90, with great interest and in great detail (!). I find them very useful (some of the most comprehensive out there I feel). I find these reviews particularly useful in light of the fact that it is so difficult to find dealers that carry stock and are willing to A/B demo most of these cartridges.

 

ortofon-cadenza-black

 

Ortofon Cadenza Black cartridge offers a very smooth sound. See April 2010 issue.

 

However, I wonder if you might be able to clarify something for me. I own a Michell Gyro (fully upgraded to near Orbe status), with Origin Live Silver MkI arm, Ortofon Kontrapunkt b cartridge (all purchased 2002) and Tom Evans Microgroove Plus (later version using newer Lithos design) phono stage. I use AVI lab series pre-power and AVI Brio loudspeakers. So it is well and truly solid-state all the way. I do find the Kontrapunkt b to be cool and emotion free (via solid state amps), as you suggest in one of your reviews. I am therefore looking to soften the sound with something easier on the ear, and I am obviously now looking to update my cartridge after 8 years of light to moderate use.


I am aware that the b (whilst something of a benchmark) is not quite state of the art. So I am looking for something better than a straight swap for the Cadenza Blue. From what you have written I feel as though I should also steer clear of the Bronze because of its treble ‘populist’ presentation. This means that I have been considering the Cadenza Black, Windfeld and A90. I have discounted the A90, largely for reasons of price, availability and it doing so little more than the Cadenza Black sonically (and sometimes less) for a lot more money.


Therefore I think it is between the Black and the Windfeld. What I can’t figure out from your review (no direct comparison is made) is which is ‘better’ generally speaking. From the frequency response graph I feel as though I should opt for the Cadenza Black. Do you think this is wise, for a solid state system? Above all, my tastes are a truthful hi-res. tonally neutral sound, with nothing added.


In case you were wondering about my arm, I intend to upgrade my Silver MkI to Mk3c when I change the cartridge.

I would really appreciate any advice you might be willing to give. Thanks a lot for your time.

best regards,

Chris Lloyd

 

We are talking about fine difference here and where Ortofon wish to go with their high end designs. The Cadenza Black is a later design than the Per Windfeld and Ortofon have honed it for a slightly darker delivery. It really was very mild mannered but you have to listen in to cartridges like this to appreciate what they are capable of and the Black was pretty damn impressive in its sound staging, detailing yet good dynamic punch that gives solid bass that’s tuneful. It’s a fantastic cartridge and more even handed than the Kontrapunkt b, but whilst you will appreciate its qualities MCs like this need an Icon Audio PS3 to do them full justice in my view. Then you’ll suddenly get a sound stage that opens right up, displaying cavernous depth. NK

 

DEALERS DO IT

I have just read Tim Jury’s letter in your November issue re the different conclusions arrived at in different magazines about whether one piece of kit is the best at that price point etc, etc...


I too read other reviews and found this, though it never troubled me as I am generally not in the market to buy. However, I think I found one reason this is so whilst reading blind tests by the public in What Hi Fi and Video. Their question usually is: do you like kit A over B or C. In this type of review, they are deciding which setup makes the test music sound the best. A reviewer will try for more objective assessments. This is particularly highlighted when you state that a piece of kit is ruthless about the quality of the source.

 

ayre_v-5xe

 

Ayre 5xe amplifier is fully balanced.

 

If you only have high quality recordings, no problem, but people will generally have bought music they enjoyed and not usually considered what studio/engineer recorded it and either not care, or just be disappointed. See where I am going with this? I think most people will see a few pieces of kit that get well reviewed, then decide which one they like hopefully after hearing it themselves. If there really was only one excellent bit of kit in each category, there would only be one hi-fi magazine. I personally, am glad it isn’t so. It’s one good reason I look forward each month to reading your mag.

keep up the good work.

Paul Clewlow.

 

Thanks Paul – your point illustrates something I always end up agonising over around October time – that of the Hi-Fi World Awards. It is so, so, so hard sometimes to come up with 'one' winner, and so arbitrary, and yet it must be done otherwise we descend into a world of seemingly complete subjectivity where we can't make up our mind about anything! I don't like doing it, I must admit, but just when I dwell on this thought then a product that's so obviously better in its category than any others comes along! Ultimately, the best hi-fi is the what you like most in your own system, in your own house, with your favourite music. DP

 

TRANSFORMER

I particularly enjoyed the November 2010 edition of H-Fi World, especially  its review of the Music First Audio Classic II preamp fitted with silver transformers. I own the Classic model fitted with larger copper transformers and can vouch for the improvement the upgrade brings. It’s a fantastic piece of equipment and I take great pleasure not just from its sound but also from its green credentials and bomb proof nature.


However, I have a hi-fi dilemma in that I am considering upgrading my current system and would appreciate your advice. I want to upgrade my power amp to one in the £3k - £5k price range but my head is spinning faster than the discs I play because of the complexity caused by connecting my sub. via its high level speaker binding post connections, to a power amp used in conjunction with the MF preamp. I would prefer to buy a power amp with properly balanced xlr inputs; I’ve put together a DIY lead that take the MF’s balanced xlr outputs to my Quad 909’s Quadlink balanced input and the sound is significantly better then the unbalanced connection.

 

mf-audio-passive-preamp

The MF Audio passive preamp with gain. Inside lies a step up transformer with isolating primary and secondary windings.

 

My system consists of the MF preamp, Quad 909 power amp, Sony xa5400es SACD/CD (sounds great with 2 channel SACD) , B&W 805s and a REL Storm 5 subwoofer.

The problem is as follows: most of the power amps in the specified price range are either monoblocks, fully balanced throughout or Class D type. These designs make it tricky to take a high level subwoofer connection of the type favoured by REL from the power amp speaker binding posts. REL have supplied me with a de-coupled lead that overcomes the danger of summing the outputs on monoblock amps, but I’ve no idea if the ground connection can be taken to the chassis of the preamp, given its passive design.


As for connecting power amps with fully balanced design such as the Ayre 5xe, how on earth is this possible without having to buy another sub?  There so many possibilities here, most of which seem likely to blow up the equipment. Normally a line-level signal fed from the preamp would solve the issue, but the MF preamp lacks a spare line-level output.

I have considered the valve route and am curious to try Icon Audio’s power amps. I’d appreciate your advice on running a sub from them. Any suggestions of power amps you have would be of interest, whether transistor or valve based. Other models I’ve considered are the Karan KAS 180 and the Ayre mentioned above.  I’ve not heard any of them, but they seem highly respected.


Another issue I have concerns matching power amp input sensitivity and impedance to the preamp.  What levels should I look at in a power amp fed from the MF?

Perhaps I’m exaggerating problems here but the proliferation of ‘exotic designs’ in power amps within the chosen price range does make things more complicated, not least of all when using a passive preamp.

Many thanks for your help.

Best regards

Paul Wizonski

 

Hi Paul. Most power amplifiers are unbalanced in themselves (internally) and just use balanced-to-unbalanced input buffer chips. Their negative loudspeaker terminal is usually connected to ground. Very few are truly balanced throughout, although bridged amplifiers by nature must not have either output terminal grounded and nor can most Class D amps.

 

You can connect the REL from the positive loudspeaker terminal to amplifier ground (i.e. the casework) and this should work, but in most cases using the negative terminal will be just the same. All amplifiers have protection circuits, by the way, and they will kick in if things are not right, providing you turn volume up slowly (i.e. do not draw too much current instantaneously).

 

So your fears are largely unfounded and nothing should blow up. Do of course take a close look at manufacturer’s warnings on what can and cannot be done with their amplifiers, before buying. Or e-mail them to ask whether the loudspeaker negative terminal can be grounded as this is a simple enough question to answer when a circuit diagram is available.

 

I am sorry to say I have not heard either of the power amplifiers you mention and both look very interesting. Fully balanced working in solid-state amplifiers does usually provide a great sound, very tidy and clean, but it is quite different to the presentation of a valve amplifier. I suggest you try and get a few demos. to see what you like, and don’t forget Quad II-eighties either.

 

Most power amps have 1V input sensitivity and 10k input impedance and this is fine for the MF preamp. NK



 

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