Watts the difference?

[grit]

Sorry for the title. I can't stand puns and have NO idea why I did it. ops:

And warning - I'm posting this in both the B&W and Rotel forums. Sorry if you read it twice.

Since the introduction of Rotel's 1077 "digital" amplifier, I've been stressing my brain on understanding an amplifiers ability to drive a speaker. My understanding is that an amplifier my supply x watts to y ohms load with z distortion, and that as the ohms increase, the amount of watts may change. And ideally, watts should be inversely proportional to ohms (eg, 100 watts at 8 ohms = 200 watts at 4 ohms). I know more power is good and not enough power will cause "clipping" and can damage speakers.

So, I'm looking at B&W 803's (50-250 watts) and 2 different brand of amplifiers in 2 power ranges... a Classe 100 watt/ch and 200 watt/ch, a Rotel 100 watt/ch and 200 watt/ch. What I'm trying to compare/understand is the difference between 100 vs 200 watts/ch within the SAME brand. The other thing I want to understand is the differences between brands (Rotel vs Classe) within the SAME watts/ch.

So, what difference does more watts make when essentially the rest of the specifications are the same? And what difference does a higher quality amplifier make when you compare the same wattage (and more importantly, what causes it)?

[Eliav]

Sorry for the title. I can't stand puns and have NO idea why I did it. ops:

And warning - I'm posting this in both the B&W and Rotel forums. Sorry if you read it twice.

Since the introduction of Rotel's 1077 "digital" amplifier, I've been stressing my brain on understanding an amplifiers ability to drive a speaker. My understanding is that an amplifier my supply x watts to y ohms load with z distortion, and that as the ohms increase, the amount of watts may change. And ideally, watts should be inversely proportional to ohms (eg, 100 watts at 8 ohms = 200 watts at 4 ohms). I know more power is good and not enough power will cause "clipping" and can damage speakers.

So, I'm looking at B&W 803's (50-250 watts) and 2 different brand of amplifiers in 2 power ranges... a Classe 100 watt/ch and 200 watt/ch, a Rotel 100 watt/ch and 200 watt/ch. What I'm trying to compare/understand is the difference between 100 vs 200 watts/ch within the SAME brand. The other thing I want to understand is the differences between brands (Rotel vs Classe) within the SAME watts/ch.

So, what difference does more watts make when essentially the rest of the specifications are the same? And what difference does a higher quality amplifier make when you compare the same wattage (and more importantly, what causes it)?

Great question !
Let me add another relevant question, are 200watts in one amp equal 200watts or even 300watts in another amp, for example, : is Bryston 7sst (600watts/8ohm 900 watts/4 ohm) "better"(=sound, dynamics,detail,punch) than Classe ca 200
( 200watts/8ohm, 400watts 4 oums) or Krell mcx ( 350w/8ohms, 700/4ohms)?.
Eliav

[miner]

Brands of amps will sound different - Rotel not as warm as Classe' but then Classe' is a bit co$$$tlier. For the B&W 803 (which B&W sounds great with Rotel products) get the 200 watt/ch - 100 watts will not do those 803 justice. Rotels are known to be underrated in watts. i.e.: my RB-1070 is rated at 130 w/ch but has been tested to be closer to 180 w/ch inot 8 ohms. I am using it to drive some B&W N804 and a ASW800 sub. For the value/dollar Rotel is tough to beat, IMHO.

[jlee]

Brands of amps will sound different - Rotel not as warm as Classe' but then Classe' is a bit co$$$tlier. For the B&W 803 (which B&W sounds great with Rotel products) get the 200 watt/ch - 100 watts will not do those 803 justice. Rotels are known to be underrated in watts. i.e.: my RB-1070 is rated at 130 w/ch but has been tested to be closer to 180 w/ch inot 8 ohms. I am using it to drive some B&W N804 and a ASW800 sub. For the value/dollar Rotel is tough to beat, IMHO.

Rotel not as warm as Classe? What do u mean by warm? I thought warm means emphasizing the midbass... and that's what Rotel does... I personally dislike the overwarmness of the Rotel... the Classe amps are much more neutral. I've had Rotel 1075, 1095, 1080, and 1090... and Classe CAM-200 and CAM-350 to compare... Rotel all have that signature Rotel midbass.

[Karma]

HI grit,
I hate jumping into this thread. I guess I love pain because I know I will fail to give you the info you want. But I'll try. I'm going to tell you more than you ever wanted to know about power. If you want to understand what the power measure technically means, read on.

To answer your question properly would take a book. Power specifications are based upon a very simple test that, like you said, measures the amount of current the amp can deliver into a specific load measured in ohms. But it's a bit more complicated than that. With audio amps, the load is typically 8 ohms but many times power is additionally specified for 4 ohms and 16 ohms. More rarely the amp will be specified at 2 ohms and even 1 ohm. Witness Krell amps, famous for their power delivery.

There is actually an industry standard that defines how to make the power measurement. To follow the standard, the power measurement is made with a very low distortion 1 kHz sine wave signal input to the amp. The voltage of the input sine wave is increased. The amplifier output signal is monitored with a Total Harmonic Distortion (THD) meter while the amp is driving the specified load (typicaly 8 ohms). When the measured THD produced by the amplifier matches the reference THD (typically .1%) the RMS (average) output voltage is measured. Power is then calculated.

So the question that is answered by the test can be thus stated: "How much power can this amplifier produce while maintaining THD below some number at 1 kHz?" As power is increased, distortion rises slowly. When the limit of the power supply is reached and it can't deliver any more current the amplifier is said to be in saturation. At saturation, distortion rises dramatically. Basically, the amp is saying "I ain't got no more to give". Going past this point will yield more measured power but it the signal becomes very dirty and, essentially, unlistenable. The amp has reached its useful limit. Sonically, the sound will become very rough and sandpaper like. It also sounds like a portable radio that needs new batteries but is much more dramatic. There is no ignoring an amp that has gone into saturation.

The reference THD is not fixed by the rules. It is only required that the number that is used be stated. It is common practice for transistor amps to use .1% THD for the reference. Tube amps are often rated at 1% THD. This is not cheating. It only reflects the fact that tube amps go into saturation more slowly than do solid state amps. This more lax reference means that a tube amp remains listenable longer, and THD increases more slowly, before total saturation is reached.

But here's the rub. The manufacturer is allowed by the rules to substitute an external power supply. Some, mostly mid-fi makers, do this. Running the test that way only measures the theoretical power of the amp. The maker is not required to state which power supply is used. In real life the amps power is limited by its power supply. The vast majority of the manufacturers in the world of high end use the regular on-board, as delivered, power supply. In fact, I don't know of any that use substitute power supplies. They want you to be impressed. Also, equipment reviewers would pick up on it in a microsecond.

Power specified at different loads demonstrates the capability of the power supply. You will notice that most amps cannot deliver twice the 8 ohm load power into a 4 ohm load. If they can, can they double again going from 4 ohms to 2 ohms? Almost never, even Krell. But some of the high end Krell's will actually do it. Some other makers can too. This is an extremely demanding test indeed and indicates a very capable power supply. And a very expensive power supply.

I have simplified power measurement a little. For example, we have not discussed how long the amp can deliver its rated power before overheating causes a melt down. It is basically is a measure of the ability of the amp to dump heat. I have also not talked about the very important Power Bandwidth specification. This test defines the ability of the amplifier to deliver power over the entire 20 Hz to 20 KHz audible frequency range. I don't think there is a standardized set of rules for this test. Someone correct me if I'm wrong.

That said, power specifications per se cannot indicate how an amp sounds when used within its limits. It only is an indicator of potential ability. The actual quality of the sound (warm, grainy, smooth, cold, etc.) is determined by the details of the circuit design. The ability to deliver power is also important. But don't place too much weight on that.

I am a believer in power. Like horsepower, you can't have too much. But one must be careful. Very often, the highest power amps are not the best sounding amps. But then again, some times they are. Just be careful to not over emphasize power in your quest for the perfect sound. Use your ears. They will reveal the truth.

Sparky

[junior77blue]

Well based on that post...

Best thing is to listen to these amps connected to your speakers and the levels you will typically listen to them and maybe a bit louder...with music that you love to listen to. And give it a wide range...classical to rock....

Let your ears make the decision.

[grit]

Karma, thanks for the response. It was very interesting and I appreciate the information. It's too bad there isn't a dedicated way all amps are rated. I know from experience the 100 wpc my old Denon pushed was nowhere NEAR the quality of my 120 wpc Rotel. And in the end, I guess I'll have to listen to make my decissions.

Two things that recently hit me like a ton of bricks :
- Room size makes a difference (some speakers can be too small or big for a room). I never imagined speakers could be too big, but it's possible.
- Quality of sound (detail, sound stage, etc.) varies with volume. It's important to conduct your listening tests at the same volume you would normally listen to music. I'm even considering using a SPL meter to make sure I've got the correct volume next time I test equipment.

So, given that I listen at what seems to be considered 'low' levels of volume, I'm trying to figure out if I can get by with my 120 wpc Rotel 1075, or if I should get a 200 watt Rotel or 100 watt Classe to power a pair of 803's.

[RebelMan]

grit, I can give you some practical feedback based on the fact that I own the 803S's and a 100wpc Rotel RSX-1056 receiver and RB-1080 outboard power amp. I have driven my 803S's with both units and to some appreciable levels. Both satisfied my typical listen behaviors. However, I was and still am reluctant to "push" the 1056 to the limits my ears could withstand because I fear the 1056 would fail to deliver the "clean" power that the 803S's and my very dynamic playback sources demanded.

However, I did attempt this with my RB-1080. Surprisingly, it was capable of satisfying my 803S's desires but only to the point of where it began to clip. Suffice it to say I reached my hearing tolerences much sooner than I did that of the limits of the 1080. What I think Karma is illustrating, and that I am sure you already are aware of, is that the quality of the power is far more important than the amount, discounting sonic signatures and other characteristics.

All of the amps you listed should satisfy your needs unless you like to drive your system hard. Under these circumtances, continous power specifications typically reported is not sufficient infomation, when speaking of SS or SESS devices. The rules change considerably when SET's are considered. Other things to consider are the speakers impedence curves and the power amplifier's ability to meet those low impedence drops.

Another often overlooked parameter is "headroom". Many manufacturer's will often leave this specification off their sheets. It can also serve as a good barameter of the amp's ability to deliver power under peak conditions given the impedence load at that time.

Also keep in mind the acoustics of a room can significant alter the sound you hear from your speakers. I have heard the 803D's in large mostly untreated room that seemed overly saturated with bass. The same speaker in another smaller room consisting of better treatments sounded much better. Moral of the story, don't judge a speaker by the room.

[caleb]

You have all missed out the most important item of all.

A very liberal helping of b/s marketing specially tailored for the American market.

[Karma]

HI grit,
Rebelman is right about headroom both of its importance and that it is usually not stated. The reason is that it is a very slippery number that varies with signal frequency, instantaneous signal power demand, and the speaker impedance (load) at that frequency. It is one of those specifications that mid fi makers use to hype their equipment but don't say so.

IMO, more power is better, within reasonable limits. You should have at least as much power as the power rating of the speaker. Generally, power amplifiers perform best if they are not delivering a large percentage of their rated power. Remember, most of the time an amp is producing only a small percentage of their specified power. Most amps can to this well. It is only during peaks that power rises to a level to be concerned about. But it is at those times when the music separates the men from the boys. Great amps can deliver the requested power instantaneously and with great authority. This effect can be heard. It's what you pay for, among other things, when you buy something like a Krell.

I'd like to add something I have not read about yet on this forum. I think B&W speakers, across the board, are some of the most rugged speakers available. When I ran my high end repair shop I purchased a pair of B&W 600i's for my workbench monitors. I did so not because they sounded good (they did) but because monitors take a terrible beating and I knew about B&W's reliability reputation. I wanted speakers that would hold up to the inevitable abuse they would receive under amplifier test conditions. They survived 6 years of punishment. Many times after a particularly shattering blast I would put my ear up to the speakers to make sure all the drivers were still working! I now use these same speakers as my surrounds in my bedroom system. They are now living a quiet, placid life in semi-retirement and are quite happy doing so. They earned their rest. They still work like new and I have never replaced a driver. That, my friends, is impressive reliability.

Sparky

[bigburner]

Hi grit,

I always thought that my RB-1080 amp (200 watts per channel into 8 ohms) was more than adequate to drive my CDM9NT speakers (3-way floorstanders, 50 - 200W into 8 ohms).

I had this belief until I invited an old friend over to watch the Cream reunion DVD on New Year's Day. My friend loves Cream, loved the DVD, and likes to listen at high volume.

To cut a long story short my Rotel was driven to the point where the protection circuit cut off the power because the amp was running so hot (you could have fried an egg on that baby). At that moment I really wanted to be the proud owner of a Rotel RB-1090 or a Bryston 4B SST or a Krell KAV-2250... you get the picture.

So in summary I agree with the members who advocate having an amp with plenty of headroom.

In defence of the RB-1080, clipping never occurred, the protection circuit worked impeccably, and normal transmission was resumed within 60 seconds (with the pre-amp turned down a notch!).

[Karma]

HI big,
Man, you guy's must have been been really cranking! It's a tribute to the speakers that they survived. Also, is the air flow to your amp OK? It just seems to me that it should not have shut down. How hot does it normally run?

Sparky

[bigburner]

Good questions Sparky. My RB-1080 is enclosed in a cabinet with sufficient space around it (see attached photo). A mains powered fan is installed at the back of the amp. There's a hole in the back of the cabinet right behind the fan to encourage the flow of air.

My Rotel amp has never been that hot before - not even close - and I've given it some pretty severe workouts in the past. I was really surprised. I must admit that it may have been a little foolhardy punishing my speakers that way. I put it down to a combination of beer consumption and an outstandingly good concert!

Occasionally this sort of behaviour is required to celebrate being alive...

[Karma]

HI big,
It seems you have paid proper attention to cooling. Must have been the concert and good friends. B&W speakers continue to impress me with their robustness. There's nothing wimpy in their design. This is a quality that should be better known.

Nice cabinet.

Sparky

[chinets]

For B&W 803's only 200 watts amps or more make them sing. They are hungry for watt power and it does make a difference as I had less power a few months ago and I was quite upset, but now wow!!. Rotel has sensational equipment like 1098/1095 combo or for Stereo 1090 amp. Rotel does produce great equipment that match B&W perfectly, and very warm in their Midrange Bass which in my opinion is perfect.

[Karma]

HI chinets,
I assume you mean "IMHO" because not everybody agrees. Like me for instance. I think Rotel's are a good buy and they do a good job with any number of speakers. I have always respected Rotel. But, IMHO (!) they are not the best. All you have to do is be willing to spend more money.

Sparky

[chinets]

Karma if you can't read english??? I assume?? I said above In My Opinion !!! Please read before critisizing, I wrote it in English pal!!! And yes there are lots of other amazing gear besides Rotel, but as an avid amateur who loves 60% HT and 40% Music and wants very good smooth and wonderful sound at a wonderful price I believe Rotel will win always hands down IMHO again for Karma to pick up!!! Yes you can always spend more and more, but for the money and quality ,and since I have 803's I believe IMHO that they make a great marriage with Rotel top end gear like 1095/1098 combo. Does that satisfy you Karma!!!

[Karma]

HI chinets,
Yes, you are right. I was too quick. I apologize. I did not mean to give offense.

In my defense, you did not put the "for the price" qualifier in your first post. Had you done so I would not quibble with your opinion. I would have agreed.

Look, both the 803D and 803S are wonderful speakers. I don't know which version you have. They are both expensive no matter which version we are talking about. They are more than good enough to show the differences between amplifiers. In general, I think people do not spend enough money on their amplifiers. As a result their speakers never get the chance to fully show their stuff. With your 803's I think you are underamped. By that I don't mean power. I'm talking about sound quality. Maybe you should check out some of the other, more expensive, less cost effective, amps mentioned on this site. Or maybe you already have in which case you have made the decision that best suits your needs.

As "avid amateurs" (that includes most of us) we are always seeking to better our systems. My comments were only intended to open another door and not dampen your enthusiasm or brand loyalty.

Sparky

[misterdoggy]

Audiogon.com is the place to find quality used Amps at great deals.

I bought 3 Krell Amps on Audiogon and paid 1/2 price of new for used Amps in perfect condition. Still 1/2 price is $3k

I had a RB1090 (300 watts a channel) and it had a great sound, until I heard a krell showcase (200 Watts a channel) which put it to shame, so throw the more watts idea out the window. Then I heard the Krell KAV 2250 which was even better, and now I've heard a 400CX (400 "A" Watts per channel).

The point is that there is no end to the madness. It can Eat you up !! :banghead:

[Karma]

HI doggy,
Three Krells? Are you same person who is suggesting that I get rid of MY Krell's? You must be trying to corner the market. Shame, shame.

BTW, I picked up my Krell KAV 280P off of Audiogon. It was a great experience. Saved a lot of money too.

Sparky

[PavelL]

Audiogon.com is the place to find quality used Amps at great deals.

I bought 3 Krell Amps on Audiogon and paid 1/2 price of new for used Amps in perfect condition. Still 1/2 price is $3k

I had a RB1090 (300 watts a channel) and it had a great sound, until I heard a krell showcase (200 Watts a channel) which put it to shame, so throw the more watts idea out the window. Then I heard the Krell KAV 2250 which was even better, and now I've heard a 400CX (400 "A" Watts per channel).

The point is that there is no end to the madness. It can Eat you up !! :banghead:

Hi, Doggy! Did you try Bryston amps with your 802Ds? Just wondering Thanks

[misterdoggy]

HI doggy,
Three Krells? Are you same person who is suggesting that I get rid of MY Krell's? You must be trying to coorner the market. Shame, shame.

BTW, I picked up my Krell KAV 280P off of Audiogon. It was a great experience. Saved a lot of money too.

Sparky

Yeah send all your Krells to my home address !!!

Karma, I meant keep your 3250 add a 2250 and a good processor and get rid of the rest. You'll have less wiring, less signal loss, and a simpler life. :T

[ED K]

Traded in my Mcintosch MC402n for a pair of Bryston 7B SST monoblocks. No comparison. The bryston brought the B&W 802Ds to life!

[chinets]

Hi Karma, Appolgy accepted.
That was very cool of you to appologize in such a sweet way. I appreciate that, and we are all here to learn. At least me!!! Thanks for all your comments about 803s that I own and your opinion on them. Could you answer the below question to help us all???


Can Karma and Misterdoggy please help the forum understand why would an Amp by Rotel 200 watts such as Rotel 1095 sound so different from the Krell let us say also a 200 w amp. and for argument sake all in 5 channel of out put 200w. What would be the different in sound you would hear..Please describe in detail!! and also what would be the difference in sound comparing both in music and again comparing both with HT?? WHAT WOULD YOU HEAR DIFFERENT?? ( IS IT A MAJOR DIFFERENCE THAT ANYONE OF THE STREET WOULD NOTICE IMMEDIATELY????AND WHAT ARE THEY???) This would be valuable information for all of us and of great interest to all of us. Thanks in advance Misterdoggy?????

[Karma]

HI chinets,
Thanks for so gracefully accepting. You have made me feel whole again.

Your question is tough. Our vocabulary is very limited and the words we do have are not understood by everyone the same way. Other members; please add to my feeble attempts. I'll give it a shot. Please remember, these are only my opinions and observations and not cosmic truths.

I'm going to use Krell amplifiers as the example since most of us have either heard Krell's or have access to a Krell dealer. This is not to say that there are not other amps available of equal or greater ability.

First, let's consider power. Power ratings are based upon steady state measurements. These numbers do not describe HOW the power is delivered. Krell amps deliver power with awesome, even explosive, authority; second to none. Some might describe this quality as "fast". You never sense that the amp has short changed the power demand. Thus, a Krell will seldom sound compressed. Krell's sound is very dynamic and true to the musical or sonic demands. This also means that Krell's exhibit great bass performance; none better.

Next there is detail and resolution. We all sort of know what this means. It's the ability of an amp to reproduce small sounds even when riding on top of big sounds. It is texture; the rosin sound of a bow, the slight crackling of a singing voice, the sharp edges of a trombone's blat, spit into the mic, discrete reverberations from the studio's walls, the soft sighing of breath passing over a flutes mouthpiece, ect. Krell's dig deep into the sonic fabric to expose the finest textures. There are endless examples. Some tube amps can do even better.

Next is grain which is related to detail. Many amps simulate detail by substituting a very fine grain that overlays and smears the sound. Tube amps do not have this defect but many solid state amps do. Krell's can do exquisite detail and remain essentially grain free. This is my primary objection to the Rotel sound. An analogy is a grainy black and white photograph. Often the grain seems to add resolution but upon closer inspection one realizes that the grain has actually reduced the resolution and replaced it with random noise.

Honesty is a hard one. A great amp essentially has no sound of its own and, therefore, no signature. If an amp has a defect, even a small defect, we will eventually hear it. It becomes a signature which we will first notice then we will anticipate it. I call this dishonesty. Great amps are honest.

Timing: Krell’s maintain excellent time relationships between and within sonic events. Again, this is related to speed. I always had a hard time with this but when it’s there, you know it. With some amps, cohesive single sonic events will seem to slightly separate themselves into discrete events. This results in time smearing. If present at all, and it usually is, the entire sonic image very slightly clouds over. It’s a little like being overlaid by a fog. Lack of clarity inhibits our ability to see through the soundstage.

The last quality I will deal with is power linearity (my term). It is the ability of an amplifier to remain true to the source material. A great amp will maintain exact voltage relationships between harmonics called for by the source. This is very difficult to discuss with examples. The closest I can come to a description is each element of a complex sonic event maintains an exact relationship to all other elements. I'll call this clarity but that does not really convey the meaning. In the final analysis, it is sonic reality. Sorry I can’t do better.

You asked if the "man of the street" can hear these qualities. I don't know. Does it matter? The real question is whether you can hear these qualities and do you care enough to pay for them. They are real and separate the great from the merely good.

I really hope someone else will jump in and help me here. I just don't have the needed words.

Sparky

[grit]

Sparky,

Forgive my short response (don't have time now), but your post was very helpful. The down-side to all of this (I presume) is that there is no meausreable trait that will indicate any of these qualities (except price)?

[Karma]

Hi grit,
You are right. The qualities I described cannot be measured objectively. Technical test equipment is just not good enough. In order to measure anything, one must know what questions to ask. We don’t even know that.

The upside is that we are born with the very best test equipment; our ears. There is nothing even close to the ears sensitivity. There’s more. We have signal processing light years ahead of any computer; our brains.

Critical listening can be learned. I was taught by a violinist friend. His main job was to convince me that I COULD hear minute differences between equipments. Once I was shown, I was on my way. He changed my life and I will be forever grateful. But it is a costly skill.

Critical listening is a state of mind akin to meditation. One must learn to pay attention to our auditory sensations. It’s easy with practice. After a while the biggest problem you will face is turning it off so you can enjoy good sound normally.

Do you listen with your eyes open or closed? The answer is critical. I find that I concentrate much more intently on my hearing if my eyes are closed. By closing my eyes, the visual part of my mental processing is shut down. When closed down visual stimulation will not cause my mind to wander down nonproductive paths. I have become so habituated to closed eye listening that I even close my eyes at live concerts! It has become reflexive. Weird huh?

You might want to give closing your eyes a try and see if it helps your critical listening abilities. I would be interested to hear about the results.

Sparky

[Eliav]

HI chinets,
Thanks for so gracefully accepting. You have made me feel whole again.

Your question is tough. Our vocabulary is very limited and the words we do have are not understood by everyone the same way. Other members; please add to my feeble attempts. I'll give it a shot. Please remember, these are only my opinions and observations and not cosmic truths.

I'm going to use Krell amplifiers as the example since most of us have either heard Krell's or have access to a Krell dealer. This is not to say that there are not other amps available of equal or greater ability.

First, let's consider power. Power ratings are based upon steady state measurements. These numbers do not describe HOW the power is delivered. Krell amps deliver power with awesome, even explosive, authority; second to none. Some might describe this quality as "fast". You never sense that the amp has short changed the power demand. Thus, a Krell will seldom sound compressed. Krell's sound is very dynamic and true to the musical or sonic demands. This also means that Krell's exhibit great bass performance; none better.

Next there is detail and resolution. We all sort of know what this means. It's the ability of an amp to reproduce small sounds even when riding on top of big sounds. It is texture; the rosin sound of a bow, the slight crackling of a singing voice, the sharp edges of a trombone's blat, spit into the mic, discrete reverberations from the studio's walls, the soft sighing of breath passing over a flutes mouthpiece, ect. Krell's dig deep into the sonic fabric to expose the finest textures. There are endless examples. Some tube amps can do even better.

Next is grain which is related to detail. Many amps simulate detail by substituting a very fine grain that overlays and smears the sound. Tube amps do not have this defect but many solid state amps do. Krell's can do exquisite detail and remain essentially grain free. This is my primary objection to the Rotel sound. An analogy is a grainy black and white photograph. Often the grain seems to add resolution but upon closer inspection one realizes that the grain has actually reduced the resolution and replaced it with random noise.

Honesty is a hard one. A great amp essentially has no sound of its own and, therefore, no signature. If an amp has a defect, even a small defect, we will eventually hear it. It becomes a signature which we will first notice then we will anticipate it. I call this dishonesty. Great amps are honest.

Timing: Krell’s maintain excellent time relationships between and within sonic events. Again, this is related to speed. I always had a hard time with this but when it’s there, you know it. With some amps, cohesive single sonic events will seem to slightly separate themselves into discrete events. This results in time smearing. If present at all, and it usually is, the entire sonic image very slightly clouds over. It’s a little like being overlaid by a fog. Lack of clarity inhibits our ability to see through the soundstage.

The last quality I will deal with is power linearity (my term). It is the ability of an amplifier to remain true to the source material. A great amp will maintain exact voltage relationships between harmonics called for by the source. This is very difficult to discuss with examples. The closest I can come to a description is each element of a complex sonic event maintains an exact relationship to all other elements. I'll call this clarity but that does not really convey the meaning. In the final analysis, it is sonic reality. Sorry I can’t do better.

You asked if the "man of the street" can hear these qualities. I don't know. Does it matter? The real question is whether you can hear these qualities and do you care enough to pay for them. They are real and separate the great from the merely good.

I really hope someone else will jump in and help me here. I just don't have the needed words.

Sparky

Hi Sparky, graet thread.
You have extensively refered to Krell as a sort of a gold standard for state of the art amplification, My understanding is that most of it's fidelity to music comes from enormous power reserves and from additional circuits which stabilize the signal and avoid distortion in lower loads such as in the fpb -cx series. What is your comment on less powerful amps. such as the 200w new Classe delta amp ?apparently, this amp is only a class A one up to the first 60watts ,it does NOT double it's power down to 2 ohms, yet it is considered very transparent, detailed,colorless, dymamic and powerful, I assume no less than for example the Krell fpb - 300cx.
In other words, two great amps with different build concepts, both obviously sound great, both are definitely premier league.. can you please comment on this.
Thanks
Eliav

[Karma]

HI Eliav,
I'll comment but I don't think I can help much. Power is good in general but it's also cheap. Much more important is how the power is delivered to the speakers. This is what we are concerned with. No one amplifier topology has the answer. Many different designs have been successful. It's just like speakers. It is the execution that counts and it is execution that is expensive.

I do not call 200W low power. That is a chunk of power adequate for almost any application. Not many years ago 200W amplifiers were rejected by the experts in favor of much smaller, but better executed amplifiers. The original Mark Levinson amps were very low powered, 25 watts I think. They were very expensive and very fine. They revolutionized high end audio. Things have changed and there are certainly great high power amps now available. Having enough power is the only really important measure. That varies depending on the size of the listening space, one's customary listening volume, type of music and the sensitivity of the speakers.

Krell a Gold Standard? Well, maybe. I like Krell very much but they are not my favorite amplifiers. I prefer tubes. Specifically, I prefer Audio Research electronics. I like several solid state amps like Rowland, Levinson, and Threshold when they were still in business. They are all great and they are all different. I'm sure there are others that I have not heard. I have no experience with Classe. I can't comment. As Misterdoggy said, at this level of performance, one's sonic taste becomes the important element. Equally important is the skill one exercises putting complementary equipment together into a coherent system where everything benefits the other.

I do know that one can safely ignore spec sheets. Your ears will reveal the truth. Depend on them.

Sparky

[Eliav]

HI Eliav,
I'll comment but I don't think I can help much. Power is good in general but it's also cheap. Much more important is how the power is delivered to the speakers. This is what we are concerned with. No one amplifier topology has the answer. Many different designs have been successful. It's just like speakers. It is the execution that counts and it is execution that is expensive.

I do not call 200W low power. That is a chunk of power adequate for almost any application. Not many years ago 200W amplifiers were rejected by the experts in favor of much smaller, but better executed amplifiers. The original Mark Levinson amps were very low powered, 25 watts I think. They were very expensive and very fine. They revolutionized high end audio. Things have changed and there are certainly great high power amps now available. Having enough power is the only really important measure. That varies depending on the size of the listening space, one's customary listening volume, type of music and the sensitivity of the speakers.

Krell a Gold Standard? Well, maybe. I like Krell very much but they are not my favorite amplifiers. I prefer tubes. Specifically, I prefer Audio Research electronics. I like several solid state amps like Rowland, Levinson, and Threshold when they were still in business. They are all great and they are all different. I'm sure there are others that I have not heard. I have no experience with Classe. I can't comment. As Misterdoggy said, at this level of performance, one's sonic taste becomes the important element. Equally important is the skill one exercises putting complementary equipment together into a coherent system where everything benefits the other.

I do know that one can safely ignore spec sheets. Your ears will reveal the truth. Depend on them.

Sparky

Thanks Sparky
Could not agree more with your last sentence !
Eliav

[grit]

Hi grit,
You are right. The qualities I described cannot be measured objectively. Technical test equipment is just not good enough. In order to measure anything, one must know what questions to ask. We don’t even know that.

The upside is that we are born with the very best test equipment; our ears. There is nothing even close to the ears sensitivity. There’s more. We have signal processing light years ahead of any computer; our brains.

Critical listening can be learned. I was taught by a violinist friend. His main job was to convince me that I COULD hear minute differences between equipments. Once I was shown, I was on my way. He changed my life and I will be forever grateful. But it is a costly skill.

Critical listening is a state of mind akin to meditation. One must learn to pay attention to our auditory sensations. It’s easy with practice. After a while the biggest problem you will face is turning it off so you can enjoy good sound normally.

Do you listen with your eyes open or closed? The answer is critical. I find that I concentrate much more intently on my hearing if my eyes are closed. By closing my eyes, the visual part of my mental processing is shut down. When closed down visual stimulation will not cause my mind to wander down nonproductive paths. I have become so habituated to closed eye listening that I even close my eyes at live concerts! It has become reflexive. Weird huh?

You might want to give closing your eyes a try and see if it helps your critical listening abilities. I would be interested to hear about the results.

Sparky

My dealer taught me to listen with my eyes closed a year ago. I've found you (and he) are absoluately correct. I can almost IMMEDIATELY hear more detail when i close my eyes. I was contemplating the idea over the last several days and came to the same hypothesis you have : By closing my eyes, the visual part of my mental processing is shut down. When closed down visual stimulation will not cause my mind to wander down nonproductive paths. Of course, when I came up with the idea, it was more like "Hey, I'll bet it's because I'm not distracted." Not nearly as articulate as your explanation.

[chinets]

Karma,
Thanks for your detailed Information that was so Informative and interesting to all of us. You have given us an insight into quality of Amps. which some of us, and that includes me , a good lesson on Amps. I am very appreciative for all your comments and I have learnt a lot in just the few paragraphs that you have written. I believe this is the spirit of the forum to learn ,learn,and learn. One can only learn from the experienced pros. and I as an amateur appreciate all this vital Info. as i could never get this Info. form anywhere except from this forum ,and from Intelligent and pros. like Karma. and some of the other contributers that have changed my view on Music and equipment. Thanks, Karma for your kind help and we bow to you for your knowledge in appreciation. This was in my opinion the best thread ever in informative marterial. THANKS PAL!!!!!!!!!!!!!! Keep it up!!