Amplifier selection for your Harbeths (general, not specific Harbeth models)

[Ned Mast]

More has been spoken about amplifier differences than perhaps needs to have been. But Don's point deserves a reply. I think he's right in stating that there must be some difference between any two amplifiers of different design and manufacture. The two questions that remain for me are 1) how significant and audible is the difference and 2) how do we determine if it is positive or negative. Unfortuantely, to the best of my knowledge, that differences are significant and audible is born out by anecdotal observations but not by double blind tests. More of the latter are needed for the sake of reliability. On the issue of positive or negative, this is entirely subjective since we have no standard by which to judge. To prefer the sound of a recording as presented by one amplifier over another means little objectively since we don't know what the actual sound of the recording is.

On the other hand, the BBC and Alan Shaw have always been rather rigorous in seeking objective evaluative procedures in designing the Harbeth speakers (eg. comparing the known sound of a voice with it's recording as played through the Harbeth), but always with the ear being important to the process.

[Kevin M]

More has been spoken about amplifier differences than perhaps needs to have been. But Don's point deserves a reply. I think he's right in stating that there must be some difference between any two amplifiers of different design and manufacture. The two questions that remain for me are 1) how significant and audible is the difference and 2) how do we determine if it is positive or negative. Unfortuantely, to the best of my knowledge, that differences are significant and audible is born out by anecdotal observations but not by double blind tests. More of the latter are needed for the sake of reliability. On the issue of positive or negative, this is entirely subjective since we have no standard by which to judge. To prefer the sound of a recording as presented by one amplifier over another means little objectively since we don't know what the actual sound of the recording is.

On the other hand, the BBC and Alan Shaw have always been rather rigorous in seeking objective evaluative procedures in designing the Harbeth speakers (eg. comparing the known sound of a voice with it's recording as played through the Harbeth), but always with the ear being important to the process.

Here's some more anecdotal stuff for us all. When I 'upgraded' my cd player, my wife batted not one eyelid. When I replaced my ancient integrated amp with a pre-power combination, hardly a murmur. When a changed my old Dynaudio speakers - which she loved - with the Compact 7s, then suddently she sat up, said how much 'different' the sound was, and spent the next hour or so pulling cd after cd from the shelves to try out. I choose to take that as a perfectly valid measure of the benefits of changing the speakers.

On a less anecdotal note, this month's Hi Fi World review four different power amps. In part, they do this using two different preamps - one costing around ?150, the other about ?850. One line that stood out to me was how their number one choice of power amp sounded equally good with both preamps - even though one cost over five times the other! Given that some preamps cost in the thousands, I do wonder what you get? I'm reminded of the graph of diminishing returns in John Crabbe's book from the late sixties (Hi-Fi in the Home).

But going back to my earlier comment about using a variable output from my cd player, this potentiometer apparently adds about ?50 to the cost of the player (currently ?1000) according to one magazine review. So it seems that apart from it's job as a switching/equalizing input levels/tone-controlling unit, my ?750 preamp seems to add zip in the way of sound quality over the output stage of the cd player. Don't get me wrong, I'm not trying to say X or Y don't matter - I'm as guilty as the next man or woman when it comes to 'upgrade-itis' - but I wonder whether I ought not to be listening to music more than hi-fi (which I guess we all strain to do when we've made a new purchase).

Of course, much of our 'insight' is erroneously based to begin with. If we accept that sound quality is our dependent variable, and that the the hi-fi chain has a number of degrees of freedom (say, 3 if you're considering source, integrated and speakers, 4 if you distinguish pre from power amp, 6 if you think the interconnect and speaker cable make a difference, 7 including speaker stands, up to any number you care to think of if the room dimensions and furnishings are considereD), then it's impossible to isolate the unique contribution of any one bit of kit without working your way through every possible combination of however many items you want to compare. Anyone got time for that? Thought not...

[A.S.]

I am greatly troubled by the concept that (especially) in credit-crisis times that a prospective customer may hesitate to buy new speakers because he fears that it is only the first rung of a ladder or excalating expenditure. We, as a company, judge our success by the number of speakers we have out in the worldwide market - I estimate about 30,000 pairs. Word of mouth is the best and most durable form of advertising and that implies that every one of those users is satisfied and enjoying music at home with whaterver amp and electronics, cables, stands they have available and within their budget. My ambition is, step by step, to double the number of Harbeth speakers in the market and the only way that can be achived is if they are all amplifier-friendly. You can not imagine how time consuming it is to reply to even one email a day asking `will amp A work with Harbeth B` - the question that we don`t ever need to be asked and we don`t need to spend time ruminating over. We don`t need to be asked this question because it is a non-issue. Harbeths will work well with every credible amplifier we have ever encountered - including kit amps providing that they have been designed and assembled correctly.

As to the very valid comment just made, we are definitely not saying ?ll amps sound the same `or even that all amps perform the same`- to do so would be foolish as there are diffferences. But those differences, under proper controlled instantaneous A/B switch-over comparisons are relatively small. Remember - both ends of the audio chain are by far the weakest parts - namely, the microphones and the speakers because these are mechanical systems and mechical systems simply cannot be perfected. Ever. To hammer this point home: imagine a scale of 1-10, 10 being perfection. Amplifiers are up at the 9.5 end of the scale - speakers, even good ones, are down about the 4 -5 level. Amps are as perfect as they need to be and in my humble opinion reached that status some years ago and can not be fundamentally improved. Its the mics and speakers where any improvements are theoretically possible, but not with current technology. Our RADIAL cone is as good as today`s technology will permit.

(I`m in Montreal - if you are in the area come and say hello at the Sheraton Centre Hotel hifi show - room acosutics are perfectly acceptable and new M40.1 working well even at the lowest frequencies in the hotel-bedroom demo room)

[DSRANCE]

All amps sound the same?

I'd say that most of the well designed ones with wide bandwidth and sensibly low distortions can sound much the same into an easy load like a Harbeth, as they're not working very hard to do the job. Indeed, when Alan first played me the P3's all those years ago, he used a humble (to my then tastes) Quad 34/306 he just happene to have in the factory. Now, at home, this Quad set always sounded boring and, well, "limp wristed" compared to the 405-2 I was then using with various pre-amps, but driving the P3's and LS3/5A's we were comparing, it was truly three dimensional, clear sounding and completely disappeared from the scene, thus hopefully backing up Alan's claims *into Harbeth speakers.*

I've always likened this HiFi hobby/obsession? as looking at different motor vehicles. Most have a wheel at each corner and an engine (usually in the front) but there are thousands of variations, some basic and frugal, others fully equipped and wastefully expensive. You take your choice.

In the same way, some enthusiasts love valves/tubes, others want huge American high current power-houses. Some go to places like Richer Sounds in the UK and buy some amazingly good products, made in the far east and not at all expensive, while others visit their audio "salon" and spend thousands of pounds on the latest "male jewellery."

As long as the products (in this case amps) are stable, reliable and competently designed, there's no reason why you can't use anything with a Harbeth and let's face it, we all like to stamp a little individuality on our hobby choices, especially when something as personal to the soul as music is involved.......

[A.S.]

I agree. "Live and let live". But what I find morally reprehensible as millions of home owners are facing reposession of their family homes is the groundless opinion that the user must spend ever more money on equipment after they buy new Harbeths chasing the illusive dream of high fidelity. That is the talk of the drug user hooked on a life of misery by his drug dealer. It is totally untrue. If I achieve nothing else here it is to promote common sense and good old fashioned pragmatism in the enjoyment of high quality music at home witha social responibility and sensitivity to those around us in society who we need to encourage, not alienate.

No wonder we`ve chased away all the women from high fidelity as customers and even listeners. A huge mistake as they have excellent ears, fine judgment and the ability to see hifi equipment for what it is ... the means to great music not the end in itself - that`s my view anyway. They also control the purse-strings. Thank goodness I`m not an audiophile!

[eelekim]

Can't agree more. For music lovers like us, it's very true. However, for audiophiles, it may be not or at least not for most of their time. People have different pastimes. Music is one of the most favourite although I don't think it's considered as important as before. Playing with audio toys is another way for enjoyment. Maybe the players can get the same joy as music lovers do with their beloved music. So equipment is surely a way to music but it's not only for music. Equipment can also be an end itself. Let's take it easy as we do for the upstream components before our trusty Harbeths.

mike

[P.C.]

I'm not sure who's saying Harbeth owners "must spend ever more money on equipment" to enable them to enjoy their speakers. But speaking for myself as an 'audiophile' (Alan states he isn't ),I'd just like to say as a hobby its something I enjoy without always spending money on it. Just reading the many reviews available is enjoyable to me. Personally I don't get stamp collectors or model boat builders but I presume they get enormous pleasure from these sometimes costly and often seemingly pointless activities. I certainly wouldn't encourage anyone bankrupting themselves in these hobbies but I expect most know how to budget their income responsibly? But I'm also a music lover, happy to listen on a clock radio. Its just that my hobby also encourages me to try to realize every musical nuance thats been captured on those magical vinyl and silver discs and I for one love the adventure.

[A.S.]

Judging by chit-chat we hear, there is a constant anxiety about amplifier/speaker combinations across the audiophile community. Having returned from the Montreal show (well attended, good quality visitors, good sounds generally throughout the show) I've had a chance to discuss this issue with visitors and other amp/speaker designers. It seems to me that the approach I've always taken of designing a Harbeth to be a universally easy-load is not shared by other speaker designers. This is a bit of a surprise, because they are, in effect, ignoring and excluding a significant proportion of potential customers for their speakers - a bizarre marketing strategy. They believe (wrongly) that their customers will cheerfully upgrade their amps/players to get the best out of those speakers. I think that's wishful thinking and a doomed business concept. It would be the equivalent of selling a flat-screen TV with inherent picture aberrations and then recommending that the customer buys expensive spectacles to correct the aberration!

Harbeth speakers are an easy load and they will work with any credible amp. If they work with any amp, we sell more speakers and don't divert precious time away from production to debating the issue of amplifiers. That strikes me as a well executed business model that all speaker designers should adopt!

[eelekim]

I think your design principle on the loading is great, especially for music lovers and general listeners. But as you're not an audiophile, you may not have a thorough idea on the minds generally found among the usual audiophiles. While you've been stressing your important point on the easy-load characteristic of your speakers, people have still been asking you or other lucky Harbeth users questions like if a certain amp could match a certain Harbeth speaker well and how much power a certain Harbeth speaker needs to perform its best. This does show their refusal to accept the fact from the designer. Sad but true.

Audiophiles, particularly those without much audio knowledge, seem like to change and spend money. There are just so many possibilities that they can obtain from the markets for their sound explorations. They don't want to stop for a "friendly" speaker. They're simply helpless. That's why they're called audiophiles. I'm glad that I'm not quite qualified as one of them.

While writing this reply, the string trio version of Bach's Goldberg Variations are played behind me by my M30. My listening position is definitely not good. I enjoy the music so much, however. I believe Harbeth is the ultimate speaker for acoustic music lovers and one of the very good speakers for the usual audiophiles in their never-ending "upgrade" path.

mike

[A.S.]

... But as you're not an audiophile, you may not have a thorough idea on the minds generally found among the usual audiophiles

This is a fair comment but not wholly correct. 30 years ago as a student I studied consumer behaviour and consumer psychology in depth. Added to this was the practical leaning gained whilst I worked for a large Japanese multinational. I am formally Qualified to comment on these matters and I can see this consumption mania for what it really is. In the 1980s audio manufacturing/selling corporations identified the 'audiophile's' psychological pressure points and have ruthlessly and cynically exploited the vulnerable, the never-satisfied and the gullible for profit regardless of the consequences for the consumer which include serious debt. When I became interested in hi-fi in the early 1970's, this was not the case, as the development of pragmatic, engineering-based BBC monitors at that time testify.

As you correctly say, I am not an 'audiophile' as I do not associate audiophilia with serious scientific best-practice where the designer is working to avoid his ears from deceiving him. Audiophiles seem to enjoy the experience of being seduced by their ears just as they would a pretty girl nibbling them, but that intimacy binds the listener to the experience and prevents him from being truly objective. They put total confidence in their hearing, despite the fact that the ears are notoriously unreliable, as anyone with a head cold will tell you and have a frequency response that is wildly non-flat and markedly degrades with age and exposure! If you want to frighten yourself with just how non-flat the ear is visit my friends here.

Put another way, the wholly subjective approach opens the potential for the listener to make a complete ass of himself in front of others with opinions that are unreliable and not repeatable, and worse, where scientific explanations are erroneously hooked to observations with rigid certainty. Trust me, I really do understand this self-delusion process because despite my own attention to detail, I am still occasionally seduced by my own ears and hear what I want to hear, especially when I am tired or the music grips me on an emotional level!

As a recent example of hearing what you want to hear I was working on a pair of speakers each of which had a lash-up crossover sitting on top - see attached pictures. You have to be very careful with the crocodile jumper leads that they don't spring off and disturb the circuit connections also that you make the same modification to both the left and right speaker, but it's far quicker than soldering/unsoldering hard joints. In this particular case, I just started to make a mod to the left crossover and I was disturbed by a phone call as I was doing it. The right crossover had not been adjusted. After the calI, assuming that I'd not made any changes to the left speaker I sat and listened to music in stereo for the rest of the day, congratulating myself on the wonderful sound etc. etc. with just the slightest awareness that it sounded different. It was only the next day after checking that all the cables were still in place that I discovered that on the left speaker during the phone call I'd inadvertently bypassed most of the tweeter circuit and it was almost directly connected to the amplifier! And I didn't notice because I don't expect or want to hear that change!

The moral of this tale is that there was a long gap whilst I took the call - I may have noticed my wiring error if I'd immediately sat to listen; any break in the listening experience will rob you of objectively comparing A v. B. This is not the first time I've astonished myself at how I can hear what I want to hear which is why my test equipment is only a couple of steps away at all times. Of course, had I measured the speaker the error would have been immediately identified and much self-delusion and design time avoided. And if I can fool myself so easily imagine how easy it is for the audiophile who has no test equipment! Pictures attached of the crossover that deceived me (my own stupid mistake).

A Harbeth is in itself a complete experience right out of the box. Ready to go, no extras needed. It will not improve or degrade, so if it's to your taste now you can be confident that it won't cheat you at some point in the future. Discussions with trusted owners reiterates that 'once they have gravitated to Harbeths they get off the upgrade roundabout' much to the delight of their wives.

All this add up to one thing - you must not trust your ears alone except under the most rigorously controlled conditions. Full stop.

>

[P.C.]

I totally agree! Which is why I also appreciate 'the serious scientific best practice' practiced by other companies such as Nordost cables (which have enabled my Harbeths to sound better than ever). They also do the hard work for us by " not trusting their own ears alone except under the most rigorously controlled conditions" and allow us to just enjoy the music.

[Markhh2]

Alan - What decisions go into you choosing an to demo your speakers with at a show? I think I recall Harbeth using DNM's on the 40.1's at CES this year, and "Class D" at some shows last year.

Can we all agree that all audio products (amps and speakers for this example) have a "sound" or a gestalt about them. I think what is is interest to most is to find out what amps etc have a sound or a gestalt that seems to work better - on a musical level - with Harbeth speakers. I have had 5 amps on my C7's from a 40 W Rotel integrated to an 8 Watt tube amp - and have worked electrically - the all produced music. My favorite now is a Mcinthosh 6900 integrated which I was able to buy from an estate at a fraction of its new cost. Now it could be that a Naim Supernait or Lavardin IT or a Duad 909/99 combo or an Audio Note 12Wattt single ended Pentode amp, may have an even better synergy with my Compact 7's. Lacking the time and available proximite dealers for these amps, I'll doubt I'll never know.

I think that most Habeth owners are in a similar boat, they LOVE their Harbeths, and what to the get the maximum amount of musical enjoyment from them. I hate swamping gear and hate spending more than I have to, but I do hate wondering if there is a similarly priced amp that would give me greater musically enjoyment.

[DSRANCE]

Markhh2, I rather think that the differences between amps is minimised when "easy" speaker loads like Harbeths are used. In my experience, amps with huge power supplies and price tags to match are simply not necessary - same as highly profitable (for the manufacturers and dealers) expensive wires..

I've just been trying to renovate an old Crown D60 power amp - a great little amp from the seventies and capable of great sound into all sorts of domestic speakers of the period, especially older "ported" designs, as long as the load is over 4 Ohms - I think it's still respectable today, despite its great age. The manual, which is written with professional engineers in mind, is full of graphs and plots of response and distortion and if you take the sensible advice given regarding cables, a superb sound ensues. Remember, everyone used long lengths of bell wire to connect their speakers back then and Crown bothered to publish a graph showing how the gauge of cable and length relative to speaker impedance and damping factor is important, especially back then before "designer cables."

Noone bothers to go into this kind of detail any more and most "audiophile" types like not knowing the science, as the results of expensive product and interconnect purchases are more "magical" with no basis in fact to spoil the fun of ones latest purchase, especially if it costs many, many times more than its manufacturing cost - I mean, a ?12500 phono stage of all things, yet they exist and some people buy them..........

[A.S.]

...Can we all agree that all audio products (amps and speakers for this example) have a "sound" or a gestalt about them. ....

No, that is too general a statement to be valid in my humble opinion. Speakers, pick-ups and microphones are electro-mechanical devices. It is quite impossible to make a perfect electro-mechanical device - there are simply too many variable to contend with. So, you can reasonably expect that according to how the designer handles those 'variables', the end product will reflect his choices, and to a greater or lesser extent will have his 'voice'. But in the case of amplifiers, it has been possible to make what is, for all intents and purposes, a perfect (solid state) amplifier for thirty years or more. How can I be so sure? Do you recall Peter Walker (QUAD founder) and his simple way of comparing the output of an amp with the input and then (the really smart bit) feeding that error signal into another amp, boosting it and listening to the mush that the test amp internally generates? You'll need to massively boost the error signal - that is, the 'corruption' of the test amp to be able to differentiate it from just hiss when monitoring on the second amp. But why should you trust me? No reason at all to do so: you can build such a circuit for just a few cents and try it yourself.

Well, that Walker comparator circuit made quite an impression on me at the time - and I built it - and whilst it definitely did not prove that all amps sound the same (or not) it did adequately make the point to me in a scientific, repeatable way that what comes out of a well designed amp working within its design envelope is 99.99% identical to what goes in, boosted by the amp's gain. Pity that you can't say that for speakers where what comes out is a shadow of what goes in (sadly).

There are a couple of caveats .... 1) the amp has to be driven within it's designer's intended power range 2) when comparing amps you *cannot* and you absolutely must not trust your ears when estimating loudness. You *have* to make a technical measurement of loudness at your ears within a fraction of a dB, or any conclusions about the 'sound' of A v. B are quite simply fallacious. That's a function of the way the ear perceives loudness. Personally, I would never, ever, under any circumstances put myself in a position where I had to compare two amplifiers and make a real value judge ment if I could not reassure myself first that I was hearing exactly the same number of decibels of music at my ears.

And to answer the question 'why do we use different amps at shows around the world' the answers are extremely simple - and not necessarily in this order ..... politics, convenience, strategic relationships, who had stock to lend us, who was sharing the cost of the room with us, who turned up on the day etc. etc.. We are so confident that Harbeths will work with any credible amp that I'd be willing to turn up to a show without an amp and hang a sign outside our room 'amp loan required for three days: apply within'.

Now for a speaker company to be that confident about the Harbeth amp/speaker performance interface I think you can take it that we see it as a non-issue. There are far more important things to worry about in life. Such as the music itself.

AS/Hong Kong

[Robmoores1]

Alan,

I know amplifier selection is a subject which has been done to death. Even so I feel it is fascinating reading the different exchanges between yourself and various Harbeth users - some who clearly agree some who don't.

I am in the camp that cannot agree with your statement that the vast majority of amplifiers sound the same and reproduce 99.99% of what it is being fed to them.

I have been experimenting with amplifiers recently and currently have two that I am playing with. One retails at around twice the price of the other. I can hear differences between the two but to highlight the differences and not just with an a/b/a comparison or blind testing.

The simple fact of the matter is that despite similar power on paper and technical specification I simply cannot get the cheaper amplifier to produce the same kind of bass no matter what level, time of day, weather, atmospheric pressure or other factor I can think of.

I also cannot get the more expensive amplifier to provide the same level of high frequency detail again o matter how hard I try. This is using the same source and cables.

I cannot see how say the capacitors in two different amplifiers can sound the same. You could argue that amplifier development over the years is merely the big companies trying to find new ways of selling you the same thing. Cannot argue with that.

But if you take someone like Dennis Morecroft of DNM - he has devoted a great deal of time to producing his own capacitors. This is a company with little advertising, daft claims or the usual rhetoric. Why would he do this if he didn't feel that it would make a difference? I am sure that he would have found better things to do.

I think that it is fair to say that Harbeth's sound good no matter what amplifier you use them with (within reason) but to say that they all sound the same is, in my humble opinion just plain wrong.

Rob

[A.S.]

...I am in the camp that cannot agree with your statement that the vast majority of amplifiers sound the same and reproduce 99.99% of what it is being fed to them....I think that it is fair to say that Harbeth's sound good no matter what amplifier you use them with (within reason) but to say that they all sound the same is, in my humble opinion just plain wrong....

With equal respect, I don't believe I have said that amps 'all sound the same' as I do not necessarily believe this. Nor is it my own experience of casually* listening to amplifiers. I have even cautioned here quite recently of my poor sonic experience with a digital switching amplifier. So I have been misquoted.

What I have said, and this applies to my observations about what we receive through all of our senses including eyes and ears, is that to one extent or another we are deceived by our senses all the time. It is so much part of the human condition that we are barely aware that all electrical input arriving from our senses at our brain is interpreted, reinterpreted, processed and then has layer upon layer of emotion laid upon it. My point is that (maybe) under properly controlled conditions those strongly held opinions of differences between item A & B are just not repeatable. In the case of amplifiers, my point was - and I stand by this a piece of science - that unless the loudness at the ears are matched (or taken into account in the evaluation process somehow) when evaluating A v B any conclusions that are drawn are not the product of science - they are the product of emotion. This is so obvious it is hardly worth stating.

Don't think for one moment that I am free from this emotional connection between ear and belief! I'm acutely aware of my own susceptibility to self-delusion. Recently, I was working on a speaker prototype. It was getting late and I was rushing. I'd inadvertently bypassed most of the crossover circuit on one channel - the tweeter was being driven directly by the amp. It's amazing that it survived. Do you think I heard the fault as I listened for a further hour to favourite music? No. I so much wanted that project to be finished that night that I vividly recall saying to myself "Eureka! Job done! Design finished!" The following morning my rested ears immediately identified the ghastly truth. See how you hear what you want to hear? I do it all the time. And I'm paid to be objective!

You can not reliably evaluate two or more pieces of audio electronics only by listening if either/or -

a) you do not match the replay level at the ears and/or
b) you can see them and/or
c) you take even as long as one second to switch from A to B and/or
d) either one is out of specification i.e. faulty in some way and/or
e) the design is so poor that the basic measurable frequency response is not comparable within a fraction of a dB and/or
f) the input, output or any other circuit part is being over-driven as is often the situation when a CD player is connected to a high sensitivity input. CD players output 2v or more under peak conditions .... can the amplifier's input stage, before the volume control, handle this huge signal cleanly? Some can't. A basic technical check will expose this (common) issue and/or
g) there may be some problem with your hearing such as tinnitus or you have a head-cold, flu or similar

In short, you have to be dead sure you're comparing like with like. That is the only truly fair comparison. I do not doubt that certain listeners would swear in the High Court on oath that A is better than B because they truly, absolutely and unflinchingly trust their ears. My point is that they have a misplaced belief in their hearing which is prone to age, disease, illness, damage, exposure and fatigue. When evaluating electronics you should not totally trust you ears except under carefully controlled conditions. I wouldn't so why would you? If under controlled conditions we can hear a difference between A & B then we can say that truly and honestly there really is a difference and we'll be able to reproduce it next week, next month, next year in Court or at home. I would be proud to wholly accept such results as valid and I would then be happy to recommend our Users here according to those results.

I don't think that I can add anything much to this as I don't want to sound like a cracked record. I've laid down my opinions which cry out for the application of the Scientific Method as our friend to guide us to better, more reasoned and long-term valid opinions at the lowest long-term cost to the consumer and I stand by that.

*key word. I mean, without first having taken the trouble to measure them to be sure that A is as loud as B and that their basic technical measurements are very similar.

AS/Kowloon, Hong Kong

[denjo]

Last night, on a whim, I replaced my Leben CS-600 with my dusty Cary 300SEI Integrated amplifier and boy was I in for a surprise! The familiar midrange magic of the 300B SET gushed through my Super HL-5s unrestrained - trumpets blared with real brass sound, I could feel the bow stretch across the violin strings and vocals came alive with uncanny realism! It was only when the music was over and the lights were on that I came back to the reality of a 300B SET with only *15 watts of power (* according to product specification)! Cary's founder, Dennis Had, wrote an article entitled "Power Corrupts" to explain why you only need 5 to 10 watts of power with the right speakers! (http://www.caryaudio.com/support/faq.html). Hearing is believing what Alan and others have often said that the Harbeths generally provide a benign impedance load, making the question of the right or ideal amplifier a non-issue! The Cary 300SEI sounded more immediate and dynamic than the Leben's 32 watts!

I then switched to my YBA Integre DT (50 watts, double toroidal) but the YBA seemed "softer" and less immediate.

So what's in a watt? Its in the quality of the watts and not the quantity of watts.

Best Regards
Dennis

[robinje]

I just wanted to post here to descibe a change in amplification of my Compact 7ES-3's. I was running them satisfactorily with a McIntosh MC275 tube amp. Out of mainly curiosity, I decided to try a pair of Wyred 4 Sound (W4S) SX-500 Class D "monoblock" solid state amps. The change is incredible! I know some folks here and elsewhere don't like Class D "ICE" amps as a whole, but the Wyred 4 Sound units are astounding in my system. They are rated at 250wpc into 8 ohms, so adequate power is not an issue. The issue there is maintaning control of the preamp volume know so as not to overpower the speakers. The new amps deliver much more detail and punch than my previous tube amp, yet sacrifice none of the "musicality" as far as I am concerned. They sound transparent, spacious, and tonally smooth to my ears. They are absolutely silent with no signal present. The W4S amps use a proprietary FET input buffer which raises the amp input impedance to 62kohms, so they are more compatible with most tube preamps than other Class D designs. This design feature is way different from other ICE-powered amps and probably is responsible for a large portion of the W4S's sound characteristics. Overall, I am thoroughly satisfied with the new amps, and given that they cost less than half of what my MC275 did is just icing on the cake! I can use the extra funds for more music...

[zenith]

I may well have posted this before as this thread is so long so sorry if this is a repeat. I have a pair of C7ES2 speakers and under normal circumstances I use them with an original Krell KSA50 amp.
This provides enough power to make any sane person run from the room asking is there any need for it to be that loud. However being a pure class A design the sound just gets louder very little signs of distortion till way past the level I would find comfortable to sit and listen to.
Recently the Krell had to have a repair to both channels as some capcitors were leaking on the circuit boards but given the unit is about 30 years old and is a very hot and hostile enviroment so it is expected.

While the unit was away I used a Mark 1 Quad 405 but with the complete board upgrade from Net Audio and I have to say they worked very well together . The changes to the Quad make a huge improvement in the area of bass control and seperation and it is oh so noticable using harbeths as while they may not delve to the very deepest depths if you get an amplifier that controls them then you will hear every little bass note.

So I do not know how well an original Quad would sound as the one I had came to me in a damaged state but I think it is probably a good budget option if you just need something to get the Harbeths singing while you decide on your ultimate killer amp. You never know you may just get carried away with the music and stop right there.

[denjo]

Zenith
While Harbeths are geberally unfussy with amplification so that they can be used with a variety of different brands, different types (Tubes, class A/B, MOSFETS and I beleive even class D), there are some particular brands that seem to have greater synergy - Quads, LFDs, Lavardins. I was quite surprised to read from your post that the Quad won the Krell in the bass region. I always thought Krels excelled with deep and tight bass.

Best Regards
Dennis