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Subject: Musical Fidelity - New 550K Supercharger product announcement
June 2007 - Musical Fidelity - NEW 550K Supercharger
Dear Fellow Music Lover,
Extra! Extra! New 550K Supercharger turns most Hi-Fi Systems into 550W dynamic power houses
The new 550K Supercharger is one of the most exciting products Musical Fidelity has ever produced. Used in a system with an amp rated between 50 and 200 Watts, it will increase its power to 550 Watts, improving the system almost beyond recognition.
"The new 550K Supercharger is a low gain power amp
that is connected to the system just before the loudspeakers.
It will dramatically increase the dynamic range of almost any
system and will enable the amplifier already in the system to function perfectly.
The 550K Supercharger turns even a modest integrated amplifier into a state-of-the-art
amplification system." Antony Michaelson
Everybody at Musical Fidelity hopes you are well. It is unusual for me to write to you at this time of year, but we have something pretty exciting to talk about, relating to the System Diagnostic 'slide rule' included with this mailing, which we will discuss later in the newsletter.
In August, we will be releasing the completely original, never-done-before 550K Supercharger. This is a most amazing product, which improves almost any hi-fi system out of all recognition.
The 550K is not the normal high-end 'upgrade', most of which cost a lot and do very little (if anything) to improve performance.
What the 550K Supercharger does is to increase the power of almost any amplifier rated between 50 and 200 watts, to 550 watts. No, that is not a misprint: it's real. Many people believe, mistakenly, that 550 watts is a vast, perhaps unnecessary, amount of power. This could not be further from the truth. 550 watts is an adequate amount of power for most loudspeakers, in most listening environments.
This level of power is needed to increase the dynamic range of a system. We do not recommend, in fact we advise against, playing a system loudly all the time. For one thing it can damage your hearing; for another, most speakers can't handle the continuous power. Transients are one thing, RMS levels are something else. And for unclipped transients, most systems need 550wpc.
I know it seems outrageous. If you want to get to grips with these ideas, read on, especially the sections where Antony explains the science behind the 550K.
Let me tell you, the 550K is a revelation. It is a fact that, when driving a loudspeaker of average sensitivity (87db), any amplifier with less than 200 watts per channel will be clipping and limiting regularly on dynamic peaks. I'm sure this all seems incredible, and the question that must occur is, 'Why don't I know about this?' The answer is that the magazines have largely ignored this vital area. Not surprisingly, most amplifier and loudspeaker manufacturers have been content with this state of affairs. Nevertheless, it is a fact that most loudspeakers need vastly more power than we have all been led to believe.
Why most upgrades are a waste of money
One of the biggest problems facing the hi-fi industry is that most so-called upgrades are nothing of the sort. Do the following situations sound familiar?
The sonic differences of the 'upgrade' have to be explained by the dealer. It is more than likely that if somebody has to tell you what you are going to hear, there is nothing there. The salesperson is suggesting what they want you to hear. As we all live in hope of getting a better sound system, and want to believe what we are told, we often hear what the dealer has suggested we are going to hear.
Upgrading always costs a huge amount of money. New cables cost a ridiculous amount of money, and unless your existing cables are in the 'bell-wire' category, offer no measurable improvement. Expensive, yes. Worthwhile, no.
Upgrading your amplifier or CD player costs a huge amount of money. Not only do you have to buy the new one, but you lose a lot of money when you sell your old one. Expensive, yes. Worthwhile, probably not.
When the dealer tries to sell you a new pair of loudspeakers, they usually suggest you need another amplifier. Expensive, yes. Necessary or worthwhile, no.
What are the results of all this upgrading? The pattern is almost always the same. A passionate, committed, music-loving audiophile starts on the 'upgrade' path and spends ever more money. Gradually it dawns on him that the new system is not much better than the one he started with. Disillusion sets in. A sad but typical story.
I've been there. Many of my friends have been there. It's shameful. We have all been kept in the dark about how to put together a system and what constitutes a real performance upgrade.
Reading amplifier reviews won't enlighten you, either. Reviewers burble on about subjective differences (imaging, grain, harshness, tonality, speed, slam, attack, etc. yawn) when the amplifier they are listening to will almost certainly be clipping regularly, so that the dominant characteristics of the total listening experience are the amplifier's clipping and the reverberant field created by the listening room.
How to make a real upgrade to your hi-fi system
The fact is, to get a real (not illusory) audible improvement in your hi-fi system,you need to go outside the usual, accepted methods. The most basic, essential and valuable thing to do is to ensure that your amplifier is not clipping and distorting. The only way to achieve this is to have sufficient power. There are no short cuts. There are no ifs, no buts and no maybes. The performance of a hi-fi system is governed by scientific laws. Either an amplifier can deliver sufficient power so that the dynamics are unclipped, or it can't.
Many people claim that their lower-powered amplifiers sound just great, with a full, rich sound and all the rest of it. They are probably enjoying a phenomenon called the reverberant field. The field is comprised of reflections, standing waves and other time-delay effects caused by the total system in a room. The paradox is that the more an amplifier is distorting and clipping, the more sound is projected into the reverberant field, and consequently the field sounds richer and fuller. But there will be little or no dynamic range, and dynamic range is one of the most important features of a hi-fi system.
It is nonsensical to talk about accuracy, linearity or any of the vital aspects of a music reproduction system, when the amplifier is spewing its distortions between the loudspeakers.
The new 550K Supercharger: A sensational way to upgrade your system without junking any of it
We have a sensational solution to this problem: the 550K Supercharger, which will deliver 550 watts to the loudspeakers. The 550K Supercharger is a low gain power amp that should be connected to the system just before the loudspeakers. You do not have to get rid of any of your existing hi-fi system, and installation is laughably easy.
a.) Disconnect your amplifier's loudspeaker cable from the loudspeaker.
b.) Connect that cable to the 550K Supercharger's input terminal.
c.) Connect the 550K Supercharger's loudspeaker cable to the loudspeaker.
d.) Plug the 550K Supercharger into the main and switch on. That's it; your done.
From now on, the Supercharger boosts the power of your existing amplifier to 550 watts. You don't have to turn it on or off, as it has auto-music sensing/muting. It will automatically switch on as soon as it senses the music signal.
This extraordinary piece of kit has a magical effect on a hi-fi system. For starters, the dynamic range will be increased by about 10dB. That is a huge amount.
The quality of the electronics in the 550K Supercharger is extraordinary. The power amp circuitry is exactly the same as in our kW550. It is laid out on a different printed circuit board, but the circuit is identical. In other words, it offers ultra-low distortion, super quality, great linearity and superlative tonal performance. It will comfortably deliver about 250 amps peak to peak,and deliver astonishing dynamic. As the circuit is the same as the kW550's, neutrality and linearity are given.
The back of the 550K Supercharger. The unit measures about 22cm (8 1/4 '') in diameter, 40cm (15 1/2'') in height, including feet.
Now, for the first time, your loudspeaker has an amplifier with sufficient power. For the first time, you will really hear what your system can do.
But there is another amazing benefit of using the Supercharger, which is so off-the-wall it will take you aback. Without
the Supercharger, your amplifier has to drive the loudspeaker. This means that it is drawing upon its full power reserves and clipping regularly. When an amplifier clips, it generates internal non-linearities, and all sorts of peculiar things happen, but one thing is certain: it will be distorting regularly.
Now, connect it to the Supercharger. The input of the Supercharger draws almost no current from the amplifier. Typically, an amplifier needs to deliver between six and ten amps into the loudspeaker, which is very demanding work. However, for the same voltage, the Supercharger will draw only about 7% of that current. In other words, your amplifier is now working perfectly: not clipping, not distorting, and not having lots of internal noise and distortions generated by having to drive the load. This is highly significant.
The result of connecting the 550K Supercharger to your existing amplifier is that your amplifier's performance is dramatically upgraded.
To recap: using the 550K Supercharger gives you a double improvement. First, you get hugely increased dynamic range due to the 550K's high power (550W / 27dBW) and second, there is a huge qualitative improvement because the existing amplifier is able to perform almost perfectly. This works with any make of amplifier, not just Musical Fidelity. And it works with valve amps as well as transistor amps and hybrids.
The sound has to be heard to be believed. Using the Supercharger with your existing amp, assuming that it is of reasonable quality, brings your amplifier up to virtually state-of-the-art level. We're not joking, nor are we making this up. These are measurable, quantifiable facts. Nobody has ever made a product like this before.
The science behind the 550K
Thank you, Indra. There are a number of elements to consider when putting together a hi-fi system:
a.) Real dynamic range requirement, based on 'the real thing',
b.) Perceived maximum sound pressure level at different distances from a loudspeaker,
c.) What amplifier power really means,
d.) Real world loudspeaker sensitivities and the implications for amplifier power,
e.) The whole system together.
This is a lot of information to absorb and to some of you it will be completely new. The magazines have largely ignored these vital topics and have made no connection between the laws of physics governing sound pressure level (SPL), amplifier power, and the desirable SPL available from a hi-fi system. Instead, they have written miles of copy about subjective irrelevancies. Most hi-fi reviews are the equivalent of a journalist examining the stitching on a the steering wheel of a car and drawing conclusions about the car's power and handling characteristics. Worse than useless. Ready for the facts? Here we go...
Dynamic Range
Dynamic range, and its role in realistic reproduction in hi-fi, is a relatively simple matter. A hi-fi system should be able to produce peak levels at the listening position close to those of live performance.
John Atkinson, the editor of Stereophile, formerly the editor of Hi-Fi News, is one of the most technically knowledgeable hi-fi journalists in the world. In a concert hall, during a classical music concert performed by a medium-size symphony orchestra, John measured 109 to 110dB peaks a the listening position. Classical music doesn't get very 'loud' compared with rock music. Rock music is much more dynamic, by at least 10dB. Tony Faulkner, one of the top recording engineers in the world, regularly measures peaks of about 120dB. So there we have it. If a system is to sound realistic, it must be able to reproduce peaks of at least 110dB SPL, without clipping.
Attenuation of perceived SPL over distance
Again, this is quite straightforward. Sound pressure level attenuates (reduces) at the rate of 6dB for each doubling of distance. This is highly relevant for loudspeaker / hi-fi systems.
All loudspeaker sensitivities are rated at one meter. Nobody listens one meter (three feet) away from the loudspeaker. Most people listen around ten to 12 feet from the loudspeakers. This means that the perceived SPL from the loudspeakers must, by the laws of physics, be at least 10dB less than at one meter from the loudspeaker. Ten dB doesn't sound like very much but an amplifier power it represents a huge increment, as you will see in the next section.
What amplifier power really means
This is where things get a bit complicated and counter-intuitive. All amplifiers are rated in watts, and always have been. But what do watts mean? Watts are linear measure of heating power and have on obvious, direct connection to the listening experience. To make the connection, watts must be translated into 'dB watts'. This simple concept is the cause of what may be the biggest misunderstanding in hi-fi.
One decibel (dB) is the minimum change in sound pressure level that a human ear can hear under ideal conditions. In practice, with a few, very small distractions, most people cannot accurately distinguish one dB difference in level. Most people can hear three dB under most conditions. Most audiophiles, if they are concentrating, can comfortably hear two dB.
Let's go back to the main discussion of amplifier power. In rough terms, each dB step requires 25 per cent greater power than the previous step. Think what that means in practical terms: for most people to be able to hear any difference in sound pressure level, you need to double the power.
Now think about this in amplifier terms. To be able to hear any difference in dynamic range between amplifier A and amplifier B, one of them must have at least double the power of the other. A significant audible difference is probably between four and six dB. Translate four to six dB into the requirement for amplifier power, and you are talking about increasing the wattage by four or five times.
This is what amplifier manufacturers don't want you to discover. After all, most of them are trying to sell you an 'upgrade' of a few watts here and there. But those few watts are of no significance.
If you have a 50 watt amplifier, the next, perhaps worthwhile, step is to 100 watts. Six dB more dynamic range., which you get by changing up from 50 to 200 watts, is worthwhile and would offer an audible improvement. When someone tries to sell you a smaller 'upgrade' form 50 watts to 75 watts, for example, you are being sold the old snake oil.
Generally, amplifier manufacturers fail to mention these fundamental truths. Instead, they will sell you power supplies, special cables and extraordinary circuit concepts (usually nothing but new words to describe an old circuit). The hard fact is, none of these things are worth anything. They won't improve your system. They are, however, well-honed strategies to part you from your hard-earned cash.
The system diagnostic slide rule. On the back there is a list of the sensitivities of some popular loudspeakers.
I know this sounds strong, but it's all true. The data about power and SPL are objective, factual, and based upon the laws of physics. If you haven't heard any of this before, it;s because it has been 'forgotten about' for decades.
Loudspeaker sensitivity and amplifier power
Most stated loudspeaker sensitivities are slightly optimistic, by one or two dB. It doesn't sound like much, but it has big consequences.
In the real world, to achieve the sound pressure level which the stated sensitivity promises, you need an amplifier of about 50 to 60 per cent more power than the stated sensitivity would suggest. Many loudspeakers are rated at 90dB sensitivity, but on technical review are found to be between 87 to 88dB. That 'minor discrepancy' of two or three dB means that you need nearly double the power to achieve what they have promised you.
John Atkinson has measured nearly 700 pairs of loudspeakers during his career, and the average sensitivity of all loudspeakers is 87dB. So, no matter what the loudspeaker manufacturers say, things are not quite as they would like you to believe.
Even worse, some high-end brands dramatically over claim their sensitivity, by as much as five or six dB. That is the equivalent of us producing an amplifier and saying that it is rated at 250 watts, when on measurement it actually delivers 65 or 70 watts. Everybody would go berserk, and rightly so.
Why is it, then, that when a loudspeaker is reviewed, and found to be five or six dB short on sensitivity, the reviewer comments blandly that it doesn't achieve its rated sensitivity, but fails to mention that the real-world impact of that shortfall is huge? Loudspeaker manufacturers are big advertisers in the magazines. Maybe the reviewers are ignorant of the numbers game that loudspeaker manufacturers are playing; if so, it's a disgraceful state of affairs. Or maybe there is another agenda at work.
Now I must get a little technical. All loudspeaker specifications assume that amplifier performance is perfect and that an amplifier's power will always double up into lower impedances. This is completely untrue. The vast majority of amplifiers available do not double their power into lower impedances, particularly at higher powers or peak levels. When you put all this together, you approach the truth. Loudspeaker sensitivities are routinely overstated by a couple of dB, and amplifiers do not deliver the power of which these speaker makers would like us to believe they are capable.
How to determine hi-fi system power requirements
To determine what power a hi-fi system needs, you must first decide what peak sound pressure level you would like your system to be able to produce. Once you have decided that, everything is fairly straightforward (but sometimes also painful or expensive).
To be classed as outstanding, a hi-fi system should reproduce the concert experience. As mentioned earlier, a medium-size classical orchestra in concert will produce dynamic peaks of 110dB, at the listening position.
An outstanding hi-fi system, therefore, is one that produces unclipped dynamic peaks of 110dB, in room, at the listening position.
A good hi-fi system will be able to produce unclipped, in room dynamic peaks at the listening position of half that level, namely 107dB. A system that might be considered reasonable should be able to produce dynamic peaks at one dB less, 106dB.
To determine how much power you need to create a system that can do these things:
a.) Select peak level.
b.) Deduct listening room attenuation factor (usually about 10 dB) from the loudspeaker sensitivity rating.
c.) Deduct remainder of b.) from a.).
d.) The remainder is your amplifier power requirement, expressed in dB.
e.) Consult the table above and translate to dB requirements from dBW into watts.
Or, you can use the System Diagnostic slide rule. This saves you the bother of doing the sums.
The art of matching amps and loudspeakers
I am sure you have twigged this by now, but there are two ways of matching amplifiers and loudspeakers. Either you can pick your loudspeaker and then find an amp to match it, or you can select your amplifier and then find a loudspeaker of sufficient sensitivity to give you the same peak level.
You can use the System Diagnostic slide rule to determine what dynamic peaks your current system should, in theory, be able to produce.
For what it's worth, we have found that higher sensitivity loudspeakers, coupled with an appropriate powered amp, always sound better and more alive than lower-sensitivity loudspeakers with higher-powered amplifier.
Our ideal system is a loudspeaker of about 90dB sensitivity with an amplifier of about 500 watts per channel: that really does the job.
'Come on, this can't be true. You're just trying to sell me a product', we hear you say
Well, of course we are trying to sell you our amplifiers. That's what we are in business to do. But it doesn't mean that we are lying to you.
What we have presented are scientific facts. The problem is that these facts have been sidelined and ignored since the early seventies.
Perhaps a little hi-fi history might help to explain the situation. In the sixties, hi-fi was getting to the point of being able to produce proper, accurate dynamic range. Back then, the vast majority of loudspeakers had about 95 to 100 dB sensitivity. What is more, they actually delivered their promised specification.
These loudspeakers were generally easy to drive, and were driven by tube amplifiers that could deliver plenty of peak volts. Things were really pretty good, from an audiophile's point of view.
110 to 115 dB peaks, at listening position, were easy.
Then came plastic woofer and tweeter loudspeakers. These new, plastic cone speakers had dramatically lower sensitivity, but they were far superior on accuracy and colouration. At the time, decent power transistors were just becoming readily available. The thinking in the industry was that transistor amplifier power would become plentiful and cheap. It seemed to follow from this that loudspeaker sensitivity was not too important, since amplifier power would be easy to provide. How naive and wrong they were!
Since then, average loudspeaker sensitivity has crept back up to 87dB, but amplifier power has not increased anywhere near enough to compensate for the overall reduction in sensitivity. As a result, today's hi-fi system is, in many respects, inferior to those of the late sixties. Shocking, isn't it?
Why 'hi-fi on the cheap' is a myth
Over the years, the idea seems to have taken root that you can have hi-fi 'on the cheap'. The hard truth is, if you want quality, you have to pay for it.
Either you go for very sensitive loudspeakers, for example Wilson, which are very expensive. Then you can couple them with a lower-powered amplifier. But remember, a very high-quality, low-powered amp is not necessarily so cheap. Or you can go for a less sensitive loudspeaker which, being more commonplace, is somewhat cheaper than the Wilson equivalent, but then you must get a much more powerful amplifier. As soon as you are in this territory, it's time for a kW550. Whichever way you want to do it, quality costs.
Of course, there is now a third way to get the power you need: with our new Supercharger.
Please don't misunderstand our message
Many people have reacted angrily to our presentation of these facts. We have received lots of letters and emails from audiophiles who have misinterpreted our position as a direct insult to their hi-fi system. Many have asked whether we are actually saying that their older, maybe less powerful, Musical Fidelity amplifier is rubbish or not even hi-fi. This could not be further from the truth.
Our message is that a hi-fi system must be able to deliver dynamic range, and this depends on matching your loudspeaker sensitivity to your amplifier power (or vice versa). This is a fundamental requirement for hi-fi, but there seems to be widespread ignorance about what it means. As a result, a lot of audiophiles have been getting ripped off for useless so-called upgrades.
We felt it was time to set the record straight. Either your loudspeakers and amplifier match in terms of sensitivity and power requirements - or they don't. If they don't, no amount of tweaking with cables and other junk is going to fix the problem.
The good news is, the 550K Supercharger will provide all the power you need. For the first time ever, you will be able to hear realistic and unclipped dynamic peaks - and your amp will be able to function as it was designed to do. Okay, back to Indra for the final word.
You owe it to yourself to hear the 550K Supercharger
Thanks, Antony. All I want to say is, even if you don't like our message, please don't just ignore the facts. If you want your hi-fi system to perform as well as is humanly possible, go and hear what the 550K can do.
All the best,
For a look at the products discussed in this newsletter, please visit our web site www.musicalfidelity.com
-
--------------------------------------------------------------------------------
MusicalFidelity
24-26 Fulton Road
Wembley, HA9 0TF
U.K.
Read the VerticalResponse marketing policy.
Subject: Musical Fidelity - New 550K Supercharger product announcement
June 2007 - Musical Fidelity - NEW 550K Supercharger
Dear Fellow Music Lover,
Extra! Extra! New 550K Supercharger turns most Hi-Fi Systems into 550W dynamic power houses
The new 550K Supercharger is one of the most exciting products Musical Fidelity has ever produced. Used in a system with an amp rated between 50 and 200 Watts, it will increase its power to 550 Watts, improving the system almost beyond recognition.
"The new 550K Supercharger is a low gain power amp
that is connected to the system just before the loudspeakers.
It will dramatically increase the dynamic range of almost any
system and will enable the amplifier already in the system to function perfectly.
The 550K Supercharger turns even a modest integrated amplifier into a state-of-the-art
amplification system." Antony Michaelson
Everybody at Musical Fidelity hopes you are well. It is unusual for me to write to you at this time of year, but we have something pretty exciting to talk about, relating to the System Diagnostic 'slide rule' included with this mailing, which we will discuss later in the newsletter.
In August, we will be releasing the completely original, never-done-before 550K Supercharger. This is a most amazing product, which improves almost any hi-fi system out of all recognition.
The 550K is not the normal high-end 'upgrade', most of which cost a lot and do very little (if anything) to improve performance.
What the 550K Supercharger does is to increase the power of almost any amplifier rated between 50 and 200 watts, to 550 watts. No, that is not a misprint: it's real. Many people believe, mistakenly, that 550 watts is a vast, perhaps unnecessary, amount of power. This could not be further from the truth. 550 watts is an adequate amount of power for most loudspeakers, in most listening environments.
This level of power is needed to increase the dynamic range of a system. We do not recommend, in fact we advise against, playing a system loudly all the time. For one thing it can damage your hearing; for another, most speakers can't handle the continuous power. Transients are one thing, RMS levels are something else. And for unclipped transients, most systems need 550wpc.
I know it seems outrageous. If you want to get to grips with these ideas, read on, especially the sections where Antony explains the science behind the 550K.
Let me tell you, the 550K is a revelation. It is a fact that, when driving a loudspeaker of average sensitivity (87db), any amplifier with less than 200 watts per channel will be clipping and limiting regularly on dynamic peaks. I'm sure this all seems incredible, and the question that must occur is, 'Why don't I know about this?' The answer is that the magazines have largely ignored this vital area. Not surprisingly, most amplifier and loudspeaker manufacturers have been content with this state of affairs. Nevertheless, it is a fact that most loudspeakers need vastly more power than we have all been led to believe.
Why most upgrades are a waste of money
One of the biggest problems facing the hi-fi industry is that most so-called upgrades are nothing of the sort. Do the following situations sound familiar?
The sonic differences of the 'upgrade' have to be explained by the dealer. It is more than likely that if somebody has to tell you what you are going to hear, there is nothing there. The salesperson is suggesting what they want you to hear. As we all live in hope of getting a better sound system, and want to believe what we are told, we often hear what the dealer has suggested we are going to hear.
Upgrading always costs a huge amount of money. New cables cost a ridiculous amount of money, and unless your existing cables are in the 'bell-wire' category, offer no measurable improvement. Expensive, yes. Worthwhile, no.
Upgrading your amplifier or CD player costs a huge amount of money. Not only do you have to buy the new one, but you lose a lot of money when you sell your old one. Expensive, yes. Worthwhile, probably not.
When the dealer tries to sell you a new pair of loudspeakers, they usually suggest you need another amplifier. Expensive, yes. Necessary or worthwhile, no.
What are the results of all this upgrading? The pattern is almost always the same. A passionate, committed, music-loving audiophile starts on the 'upgrade' path and spends ever more money. Gradually it dawns on him that the new system is not much better than the one he started with. Disillusion sets in. A sad but typical story.
I've been there. Many of my friends have been there. It's shameful. We have all been kept in the dark about how to put together a system and what constitutes a real performance upgrade.
Reading amplifier reviews won't enlighten you, either. Reviewers burble on about subjective differences (imaging, grain, harshness, tonality, speed, slam, attack, etc. yawn) when the amplifier they are listening to will almost certainly be clipping regularly, so that the dominant characteristics of the total listening experience are the amplifier's clipping and the reverberant field created by the listening room.
How to make a real upgrade to your hi-fi system
The fact is, to get a real (not illusory) audible improvement in your hi-fi system,you need to go outside the usual, accepted methods. The most basic, essential and valuable thing to do is to ensure that your amplifier is not clipping and distorting. The only way to achieve this is to have sufficient power. There are no short cuts. There are no ifs, no buts and no maybes. The performance of a hi-fi system is governed by scientific laws. Either an amplifier can deliver sufficient power so that the dynamics are unclipped, or it can't.
Many people claim that their lower-powered amplifiers sound just great, with a full, rich sound and all the rest of it. They are probably enjoying a phenomenon called the reverberant field. The field is comprised of reflections, standing waves and other time-delay effects caused by the total system in a room. The paradox is that the more an amplifier is distorting and clipping, the more sound is projected into the reverberant field, and consequently the field sounds richer and fuller. But there will be little or no dynamic range, and dynamic range is one of the most important features of a hi-fi system.
It is nonsensical to talk about accuracy, linearity or any of the vital aspects of a music reproduction system, when the amplifier is spewing its distortions between the loudspeakers.
The new 550K Supercharger: A sensational way to upgrade your system without junking any of it
We have a sensational solution to this problem: the 550K Supercharger, which will deliver 550 watts to the loudspeakers. The 550K Supercharger is a low gain power amp that should be connected to the system just before the loudspeakers. You do not have to get rid of any of your existing hi-fi system, and installation is laughably easy.
a.) Disconnect your amplifier's loudspeaker cable from the loudspeaker.
b.) Connect that cable to the 550K Supercharger's input terminal.
c.) Connect the 550K Supercharger's loudspeaker cable to the loudspeaker.
d.) Plug the 550K Supercharger into the main and switch on. That's it; your done.
From now on, the Supercharger boosts the power of your existing amplifier to 550 watts. You don't have to turn it on or off, as it has auto-music sensing/muting. It will automatically switch on as soon as it senses the music signal.
This extraordinary piece of kit has a magical effect on a hi-fi system. For starters, the dynamic range will be increased by about 10dB. That is a huge amount.
The quality of the electronics in the 550K Supercharger is extraordinary. The power amp circuitry is exactly the same as in our kW550. It is laid out on a different printed circuit board, but the circuit is identical. In other words, it offers ultra-low distortion, super quality, great linearity and superlative tonal performance. It will comfortably deliver about 250 amps peak to peak,and deliver astonishing dynamic. As the circuit is the same as the kW550's, neutrality and linearity are given.
The back of the 550K Supercharger. The unit measures about 22cm (8 1/4 '') in diameter, 40cm (15 1/2'') in height, including feet.
Now, for the first time, your loudspeaker has an amplifier with sufficient power. For the first time, you will really hear what your system can do.
But there is another amazing benefit of using the Supercharger, which is so off-the-wall it will take you aback. Without
the Supercharger, your amplifier has to drive the loudspeaker. This means that it is drawing upon its full power reserves and clipping regularly. When an amplifier clips, it generates internal non-linearities, and all sorts of peculiar things happen, but one thing is certain: it will be distorting regularly.
Now, connect it to the Supercharger. The input of the Supercharger draws almost no current from the amplifier. Typically, an amplifier needs to deliver between six and ten amps into the loudspeaker, which is very demanding work. However, for the same voltage, the Supercharger will draw only about 7% of that current. In other words, your amplifier is now working perfectly: not clipping, not distorting, and not having lots of internal noise and distortions generated by having to drive the load. This is highly significant.
The result of connecting the 550K Supercharger to your existing amplifier is that your amplifier's performance is dramatically upgraded.
To recap: using the 550K Supercharger gives you a double improvement. First, you get hugely increased dynamic range due to the 550K's high power (550W / 27dBW) and second, there is a huge qualitative improvement because the existing amplifier is able to perform almost perfectly. This works with any make of amplifier, not just Musical Fidelity. And it works with valve amps as well as transistor amps and hybrids.
The sound has to be heard to be believed. Using the Supercharger with your existing amp, assuming that it is of reasonable quality, brings your amplifier up to virtually state-of-the-art level. We're not joking, nor are we making this up. These are measurable, quantifiable facts. Nobody has ever made a product like this before.
The science behind the 550K
Thank you, Indra. There are a number of elements to consider when putting together a hi-fi system:
a.) Real dynamic range requirement, based on 'the real thing',
b.) Perceived maximum sound pressure level at different distances from a loudspeaker,
c.) What amplifier power really means,
d.) Real world loudspeaker sensitivities and the implications for amplifier power,
e.) The whole system together.
This is a lot of information to absorb and to some of you it will be completely new. The magazines have largely ignored these vital topics and have made no connection between the laws of physics governing sound pressure level (SPL), amplifier power, and the desirable SPL available from a hi-fi system. Instead, they have written miles of copy about subjective irrelevancies. Most hi-fi reviews are the equivalent of a journalist examining the stitching on a the steering wheel of a car and drawing conclusions about the car's power and handling characteristics. Worse than useless. Ready for the facts? Here we go...
Dynamic Range
Dynamic range, and its role in realistic reproduction in hi-fi, is a relatively simple matter. A hi-fi system should be able to produce peak levels at the listening position close to those of live performance.
John Atkinson, the editor of Stereophile, formerly the editor of Hi-Fi News, is one of the most technically knowledgeable hi-fi journalists in the world. In a concert hall, during a classical music concert performed by a medium-size symphony orchestra, John measured 109 to 110dB peaks a the listening position. Classical music doesn't get very 'loud' compared with rock music. Rock music is much more dynamic, by at least 10dB. Tony Faulkner, one of the top recording engineers in the world, regularly measures peaks of about 120dB. So there we have it. If a system is to sound realistic, it must be able to reproduce peaks of at least 110dB SPL, without clipping.
Attenuation of perceived SPL over distance
Again, this is quite straightforward. Sound pressure level attenuates (reduces) at the rate of 6dB for each doubling of distance. This is highly relevant for loudspeaker / hi-fi systems.
All loudspeaker sensitivities are rated at one meter. Nobody listens one meter (three feet) away from the loudspeaker. Most people listen around ten to 12 feet from the loudspeakers. This means that the perceived SPL from the loudspeakers must, by the laws of physics, be at least 10dB less than at one meter from the loudspeaker. Ten dB doesn't sound like very much but an amplifier power it represents a huge increment, as you will see in the next section.
What amplifier power really means
This is where things get a bit complicated and counter-intuitive. All amplifiers are rated in watts, and always have been. But what do watts mean? Watts are linear measure of heating power and have on obvious, direct connection to the listening experience. To make the connection, watts must be translated into 'dB watts'. This simple concept is the cause of what may be the biggest misunderstanding in hi-fi.
One decibel (dB) is the minimum change in sound pressure level that a human ear can hear under ideal conditions. In practice, with a few, very small distractions, most people cannot accurately distinguish one dB difference in level. Most people can hear three dB under most conditions. Most audiophiles, if they are concentrating, can comfortably hear two dB.
Let's go back to the main discussion of amplifier power. In rough terms, each dB step requires 25 per cent greater power than the previous step. Think what that means in practical terms: for most people to be able to hear any difference in sound pressure level, you need to double the power.
Now think about this in amplifier terms. To be able to hear any difference in dynamic range between amplifier A and amplifier B, one of them must have at least double the power of the other. A significant audible difference is probably between four and six dB. Translate four to six dB into the requirement for amplifier power, and you are talking about increasing the wattage by four or five times.
This is what amplifier manufacturers don't want you to discover. After all, most of them are trying to sell you an 'upgrade' of a few watts here and there. But those few watts are of no significance.
If you have a 50 watt amplifier, the next, perhaps worthwhile, step is to 100 watts. Six dB more dynamic range., which you get by changing up from 50 to 200 watts, is worthwhile and would offer an audible improvement. When someone tries to sell you a smaller 'upgrade' form 50 watts to 75 watts, for example, you are being sold the old snake oil.
Generally, amplifier manufacturers fail to mention these fundamental truths. Instead, they will sell you power supplies, special cables and extraordinary circuit concepts (usually nothing but new words to describe an old circuit). The hard fact is, none of these things are worth anything. They won't improve your system. They are, however, well-honed strategies to part you from your hard-earned cash.
The system diagnostic slide rule. On the back there is a list of the sensitivities of some popular loudspeakers.
I know this sounds strong, but it's all true. The data about power and SPL are objective, factual, and based upon the laws of physics. If you haven't heard any of this before, it;s because it has been 'forgotten about' for decades.
Loudspeaker sensitivity and amplifier power
Most stated loudspeaker sensitivities are slightly optimistic, by one or two dB. It doesn't sound like much, but it has big consequences.
In the real world, to achieve the sound pressure level which the stated sensitivity promises, you need an amplifier of about 50 to 60 per cent more power than the stated sensitivity would suggest. Many loudspeakers are rated at 90dB sensitivity, but on technical review are found to be between 87 to 88dB. That 'minor discrepancy' of two or three dB means that you need nearly double the power to achieve what they have promised you.
John Atkinson has measured nearly 700 pairs of loudspeakers during his career, and the average sensitivity of all loudspeakers is 87dB. So, no matter what the loudspeaker manufacturers say, things are not quite as they would like you to believe.
Even worse, some high-end brands dramatically over claim their sensitivity, by as much as five or six dB. That is the equivalent of us producing an amplifier and saying that it is rated at 250 watts, when on measurement it actually delivers 65 or 70 watts. Everybody would go berserk, and rightly so.
Why is it, then, that when a loudspeaker is reviewed, and found to be five or six dB short on sensitivity, the reviewer comments blandly that it doesn't achieve its rated sensitivity, but fails to mention that the real-world impact of that shortfall is huge? Loudspeaker manufacturers are big advertisers in the magazines. Maybe the reviewers are ignorant of the numbers game that loudspeaker manufacturers are playing; if so, it's a disgraceful state of affairs. Or maybe there is another agenda at work.
Now I must get a little technical. All loudspeaker specifications assume that amplifier performance is perfect and that an amplifier's power will always double up into lower impedances. This is completely untrue. The vast majority of amplifiers available do not double their power into lower impedances, particularly at higher powers or peak levels. When you put all this together, you approach the truth. Loudspeaker sensitivities are routinely overstated by a couple of dB, and amplifiers do not deliver the power of which these speaker makers would like us to believe they are capable.
How to determine hi-fi system power requirements
To determine what power a hi-fi system needs, you must first decide what peak sound pressure level you would like your system to be able to produce. Once you have decided that, everything is fairly straightforward (but sometimes also painful or expensive).
To be classed as outstanding, a hi-fi system should reproduce the concert experience. As mentioned earlier, a medium-size classical orchestra in concert will produce dynamic peaks of 110dB, at the listening position.
An outstanding hi-fi system, therefore, is one that produces unclipped dynamic peaks of 110dB, in room, at the listening position.
A good hi-fi system will be able to produce unclipped, in room dynamic peaks at the listening position of half that level, namely 107dB. A system that might be considered reasonable should be able to produce dynamic peaks at one dB less, 106dB.
To determine how much power you need to create a system that can do these things:
a.) Select peak level.
b.) Deduct listening room attenuation factor (usually about 10 dB) from the loudspeaker sensitivity rating.
c.) Deduct remainder of b.) from a.).
d.) The remainder is your amplifier power requirement, expressed in dB.
e.) Consult the table above and translate to dB requirements from dBW into watts.
Or, you can use the System Diagnostic slide rule. This saves you the bother of doing the sums.
The art of matching amps and loudspeakers
I am sure you have twigged this by now, but there are two ways of matching amplifiers and loudspeakers. Either you can pick your loudspeaker and then find an amp to match it, or you can select your amplifier and then find a loudspeaker of sufficient sensitivity to give you the same peak level.
You can use the System Diagnostic slide rule to determine what dynamic peaks your current system should, in theory, be able to produce.
For what it's worth, we have found that higher sensitivity loudspeakers, coupled with an appropriate powered amp, always sound better and more alive than lower-sensitivity loudspeakers with higher-powered amplifier.
Our ideal system is a loudspeaker of about 90dB sensitivity with an amplifier of about 500 watts per channel: that really does the job.
'Come on, this can't be true. You're just trying to sell me a product', we hear you say
Well, of course we are trying to sell you our amplifiers. That's what we are in business to do. But it doesn't mean that we are lying to you.
What we have presented are scientific facts. The problem is that these facts have been sidelined and ignored since the early seventies.
Perhaps a little hi-fi history might help to explain the situation. In the sixties, hi-fi was getting to the point of being able to produce proper, accurate dynamic range. Back then, the vast majority of loudspeakers had about 95 to 100 dB sensitivity. What is more, they actually delivered their promised specification.
These loudspeakers were generally easy to drive, and were driven by tube amplifiers that could deliver plenty of peak volts. Things were really pretty good, from an audiophile's point of view.
110 to 115 dB peaks, at listening position, were easy.
Then came plastic woofer and tweeter loudspeakers. These new, plastic cone speakers had dramatically lower sensitivity, but they were far superior on accuracy and colouration. At the time, decent power transistors were just becoming readily available. The thinking in the industry was that transistor amplifier power would become plentiful and cheap. It seemed to follow from this that loudspeaker sensitivity was not too important, since amplifier power would be easy to provide. How naive and wrong they were!
Since then, average loudspeaker sensitivity has crept back up to 87dB, but amplifier power has not increased anywhere near enough to compensate for the overall reduction in sensitivity. As a result, today's hi-fi system is, in many respects, inferior to those of the late sixties. Shocking, isn't it?
Why 'hi-fi on the cheap' is a myth
Over the years, the idea seems to have taken root that you can have hi-fi 'on the cheap'. The hard truth is, if you want quality, you have to pay for it.
Either you go for very sensitive loudspeakers, for example Wilson, which are very expensive. Then you can couple them with a lower-powered amplifier. But remember, a very high-quality, low-powered amp is not necessarily so cheap. Or you can go for a less sensitive loudspeaker which, being more commonplace, is somewhat cheaper than the Wilson equivalent, but then you must get a much more powerful amplifier. As soon as you are in this territory, it's time for a kW550. Whichever way you want to do it, quality costs.
Of course, there is now a third way to get the power you need: with our new Supercharger.
Please don't misunderstand our message
Many people have reacted angrily to our presentation of these facts. We have received lots of letters and emails from audiophiles who have misinterpreted our position as a direct insult to their hi-fi system. Many have asked whether we are actually saying that their older, maybe less powerful, Musical Fidelity amplifier is rubbish or not even hi-fi. This could not be further from the truth.
Our message is that a hi-fi system must be able to deliver dynamic range, and this depends on matching your loudspeaker sensitivity to your amplifier power (or vice versa). This is a fundamental requirement for hi-fi, but there seems to be widespread ignorance about what it means. As a result, a lot of audiophiles have been getting ripped off for useless so-called upgrades.
We felt it was time to set the record straight. Either your loudspeakers and amplifier match in terms of sensitivity and power requirements - or they don't. If they don't, no amount of tweaking with cables and other junk is going to fix the problem.
The good news is, the 550K Supercharger will provide all the power you need. For the first time ever, you will be able to hear realistic and unclipped dynamic peaks - and your amp will be able to function as it was designed to do. Okay, back to Indra for the final word.
You owe it to yourself to hear the 550K Supercharger
Thanks, Antony. All I want to say is, even if you don't like our message, please don't just ignore the facts. If you want your hi-fi system to perform as well as is humanly possible, go and hear what the 550K can do.
All the best,
For a look at the products discussed in this newsletter, please visit our web site www.musicalfidelity.com
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MusicalFidelity
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Wembley, HA9 0TF
U.K.
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