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May 2011 issue - Page 3

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May 2011 issue
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WHAT I REALLY WANT

I wish to have a new audio system capable to break the boundaries between me and the musicians. I do not really care about the hypes of high-end; you know what they are, I do not care about fake hyper details for example. What I really want is power to recreate the musical event in my listening room. I want to turn up and up the volume control without sign of strain, without compression and without distortions, with grunt at low frequencies; yeah I want to feel the air moved by the woofers like a guitar player in front of valve Marshall stacks.

 

I have got old good memory by Linn Isobarik tri-amplified with electronic crossover and power amplifiers, and the same good feeling by Rogers LS 5/8 system with matched Quad power amplifiers. That is the sound of high fidelity for me, something capable to stand me up from the listening coach (couch?) and induce me to dance and have good times.

My personal music preferences are rock’n’roll of course, but I listen literally to all kinds of good music. Equally important is the fact that I do not want to spend an arm and a leg to achieve this goal, let us say up to 10 to 12k all included, turntable/arm/cartridge + CD player + integrated or separate amplifiers (I do not care which format) + loudspeakers and all cables. If the amplifier can manage music, from modern sources like iPod and the likes (DAB, Ethernet etc) could be definitively considered a bonus.

 

Please I would be glad to read opinion from both David and Noel. Thanks for your competent and invaluable help.

Best regards,

Lou (Cesare Augusto)


monitor-audio-pl300

Monitor Audio PL300 offers a clean, fast sound from a ribbon tweeter and C-CAM treated alloy drive units.

 

Monitor Audio PL300s get close to the Isobarik in some senses, being a loudspeaker designed to Rock. Monitor Audio introduced less expensive Gold variants at this year's Bristol Show and they may suit you too. NK

 

Hmmm... you want all this for twelve grand? I’m afraid you’re into Usher Be-10 territory for the sort of power and punch you used to get from your old tri-amp Isobarik set-up, and these cost £11,000 for starters. These are, in my view, seminal rock loudspeakers; whilst they don’t have the midband fluency of top Tannoys, they have massive scale and power and depth and precision; anything else sounds a tad too domesticated for no holds barred rock in my view. I would be tempted to purchase these and then slowly build your system around it. This could be done by purchasing secondhand, and/or in steps, but if you’re as sure as you sound that you want a ‘boundary breaking’ system then this is really the only way...

 

My plan of attack would be to buy a new Michell GyroDec SE/Tecnoarm, fit an Audio Technica AT33MC cartridge and an Icon Audio PS1.2 phono stage. This will give you a really good analogue source that’s upgradeable but not in any immediate need of upgrading. Then you’re looking at buying an Arcam rDAC and plugging it into your computer; it has the superb dCS Asynchronous USB system so will get a very stable, low-jitter digital audiostream from your PC or Mac’s USB output; it will also give your existing CD player (or whatever other digital source you have) a decent shot-in-the-arm; all for under £300. Next is amplification; as a stop gap, look at an Icon Audio 300B II integrated amplifier. Not only is this a nice smooth source for super revealing ushers, it has a bit of oomph in the bass giving a nicely ‘gutsy’ sound. There was real synergy between  this and the NS1000Ms in my system, and the NS1000Ms are similar to the Be-10s in many respects. I’m afraid this will have taken you closer to £14k than £12k, but it’s the beginnings of a stunning top end system.

 

After the Icon Audio 300B has served its time, come back to us for that all-important choice of pre and power amps; there’s a vast choice depending on your taste and how you feel you’re getting on with the system as it is. You’d also then be advised to get a Cyrus SE transport for your CDs, and upgrade the Gyro to Orbe spec, with a possible move to a high end arm; we’d be happy to advise!  DP

 

ARCAM LOCK

I have locked myself into Arcam over the years! My system consists of Arcam FMJ CD37, C31, P35 (a pair set in Mono, HF) plus 2 x P1s (Pair LF). I am using Atlas Elektra/Ichor cabling throughout the system. I have a Isotek Titan GII and a Isol-8 Powerline Axis for mains conditioning.


The speakers I am currently using are Usher Mini Dancer Two floorstanders, in a room 16ft(L) x 14ft (w) x 11ft (h). As delighted as I am with this setup, I am craving more resolution and detail, while also adding as much as possible an open/deep soundstage for my predominately Jazz based CD collection. As good as the CD37 is I am tinkering with the idea of replacing it with the likes of Krell’s new S-350A or Moon’s CD3.3, which I feel may give me these qualities as well as a tighter/deeper bass, and more defined treble for the Ushers Beryllium tweeters! I am aspiring also to replace the Mini Dancer Two’s with the Be-10 at a later stage. Currently have a budget of about £3k..........

Your guidance greatly appreciated.

Dave Walsh


electrocompaniet-emc-1up

Electrocompaniet EMC-1UP DAC has a sense of life unmatched at the price, says David.

 

I’d certainly say the Moon CD3.3 is a very worthy contender, but in terms of both outright performance and system synergy, at this price point it would have to be the Electrocompaniet EMC-1UP, which has a deeper and darker sound, along with a more robust bass and sense of life that I feel is unmatched at the price. Especially if you’re aiming towards Usher Be-10s, you want to get as fulsome sounding source component as you possibly can, and the EMC-1UP is certainly this. DP

 

REMEDY

I have a very irritating problem and would be grateful if you could suggest a remedy. When I first start up my system and start the CD player, on many occasions I get sound from only one speaker. The left speaker plays but the right hand has no sound. This problem is strange because half the time it plays perfectly normally. I have purchased and fitted new interconnects to try and fix the problem, to no avail. My system comprises Arcam CD 73, Arcam A75 amp. and Dali Lector 2 speakers.  I would be very grateful for any advice you can give.

J. Chantry

Doncaster

 

We can’t fault find at a distance, only suggest ways to track down the problem.

 

First, find whether it is only the CD player that gives one channel. If so, then the amp and loudspeakers are OK. You then need to replace the CD interconnect. If this does nothing the fault lies in the CD player and it needs repair or replacement. It could conceivably be the amplifier’s input switching, in which case plug your CD player into AUX, or any line input, even Tape. In this case the amplifier is faulty of course.

 

If the fault affects all sources then the problem lies in the amplifier or loudspeakers. Swap the loudspeaker leads around on the amplifier. If the fault stays in the same channel, then one loudspeaker is a fault. If the fault swaps channels then the amplifier is at fault. It may be the output protection relays, or input switching.

 

If a loudspeaker is intermittent like this (unlikely) try checking / replacing connections. I hope this advice gives a way to isolate the fault and have it fixed. Good luck. NK

 

DAMPING

When measuring amplifier performance, resident expert Noel Keywood routinely comments on damping factor. For example, "damping factor was surprisingly low at 16” and “damping factor was very low at 21” are comments to be found in the January 2011 issue.

 

In order to help put these comments into perspective, I hope Noel will bear with me as I define damping factor and attempt to explain its significance in sound reproduction. Noel’s superior knowledge of the subject will be required at the conclusion of my ramblings!

 

Damping factor is defined as the ratio of loudspeaker impedance to amplifier source impedance. If the amplifier source impedance is low in comparison with the loudspeaker impedance, then the low frequency resonance is brought under better control and the loudspeaker follows more closely the electrical signal from the amplifier.

In effect, the higher the damping factor, the higher the damping of the loudspeaker’s bass resonance and the higher the quality of the bass reproduction.

 

I once read (admittedly in the dim and distant past!) that damping factors in excess of 5 bring diminishing returns in terms of quality of bass reproduction. This presumption is clearly at odds with Noel’s comments!

 

Over to you Noel! How high a damping factor do you recommend, taking into account the impedance characteristics of today’s loudspeakers?

In addition, would you please enlighten me as to which aspects of amplifier design bear directly on damping factor?

Alan RJ Scott


df-diag

 

The many influences upon Damping Factor are shown here and given a typical value. The amp. here would be rated at 80, but the drive unit 'sees' just 6.

 

Hi Alan. It is impossible to be precise about this but here is a guide, based on measuring Damping Factor and then listening to the amplifier concerned, with both lightly damped and heavily damped loudspeakers. The rule of thumb value commonly used as a low / high break point is 20 and I broadly agree with this. Below 5 an amplifier quite obviously exerts little bass control and such a figure exists with Single-Ended valve amps lacking feedback. No great problem here, providing they are used with reasonably well damped loudspeakers (no bass peak), like Triangle Antals. Valve amps with feedback sit in the 5-15 Damping Factor range (with an 8 Ohm resistor). Transistor amps generally run from 20-80. Anything above 20 exerts quite good subjective control. Note that Naim amps consistently measure 17, an interesting exception.

 

Our in-house Spendor S8es loudspeakers are under damped and boom with zero feedback SE amps, but sound controlled with our grippy Musical Fidelity AMS50 amplifier.

I hope this gives you some feel for the subject.

 

I have found it is best to use a low DF amp with a well damped loudspeaker, and a high DF amp with a lightly damped loudspeaker, broadly speaking. High damping factor figures (low output impedance) are not a figure of goodness in themselves.

 

There are three damping mechanisms in a loudspeaker, the great Laurie Fincham of KEF once explained to me: acoustic, magnetic and electrical. Broadly speaking, if a loudspeaker peaks up in its bass response, as many do, then it is lightly damped. If it rolls away steadily below about 200Hz it is well damped. Note that the latter suits wall placement and explains why small/medium sized wall mounters of yore gave ‘tight bass’ when driven loud by a Naim or Linn amplifier.

 

I’m sorry it is not all a bit simpler – but it just isn’t! Feedback reduces output impedance in an amplifier, be it transistor or valve. Transistor amps can accept and also need higher feedback (to suppress distortion). NK



 

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