What makes a high end audio amp "better" then a low end unit?

[Cliff Matthews]

And then there's Nelson Pass... He must be one of the oldest amp designers on the planet.
https://www.youtube.com/results?search_query=Nelson+Pass+lecturing+at+the+Burning+Amp

[grifftech]

less mains hum and noise

[b_force]

There is yet another important factor in the reproduction of the sound that no one has spoken of, and yet it is essential, the acoustics of the local.

It's funny to see that people are focusing their attention specifically on amplifiers when there are many other more important factors.

Well yes, that's actually the whole point, bit I didn't wanna go all that way, but it was essentially what I meant.
If you put it all in perspective the amplifier is one of the very last things you need to put effort in.

[Circlotron]

It's funny to see that people are focusing their attention specifically on amplifiers when there are many other more important factors.

They’re just staying on topic, addressing the original question.

[Zero999]

less mains hum and noise

It's possible to design a good, low cost, audio amplifier, with virtually imperceptible levels of noise.

[oldway]

It's funny to see that people are focusing their attention specifically on amplifiers when there are many other more important factors.

They’re just staying on topic, addressing the original question.

When we say "What makes a high end audio amp" better "then a low end unit?", We do not ask a question, we say that a high end audio amp is " better "then a low end unit....Is it true ?

It's an assertion disguised as a question....

[oldway]

It's funny to see that people are focusing their attention specifically on amplifiers when there are many other more important factors.

They’re just staying on topic, addressing the original question.

When we say "What makes a high end audio amp" better "then a low end unit?", We do not ask a question, we say that a high end audio amp is " better "then a low end unit....Is it true ?

It's an assertion disguised as a question....

[coppice]

The audio amplifier is a problem which was solved over 40 years ago.

Actually 40 years ago (mid 70s) is when a lot of audio amplifier problems were being created. That was the era of 1MHz bandwidth audio amps, with masses of negative feedback, and bizarre transient performance. It was the mid to late 80s before the industry settled down to more sane designs, with proper testing of transient performance.

More recently the move to switch mode amps, to allow things like compact and powerful 7.1 designs, created its own performance issues. Again, most of this was due to a focus on static testing, and too little transient testing. This is only now settling down.

The QUAD 303, from 50 years ago, was one of the first all-transistor audio power amplifiers to be essentially 'perfect' (within its bandwidth, voltage swing, and load impedance limits, of course). Any more recent design that isn't 'perfect' has been done wrong!

The QUAD 303 was an excellent amp, if a bit overpriced. There were quite a few good transistor amps 50 years ago, from Europe, Japan and the US. Then the industry went crazy, and most manufacturers, especially the high volume ones, produced terrible amps for some years.

[wraper]

And then there's Nelson Pass... He must be one of the oldest amp designers on the planet.
https://www.youtube.com/results?search_query=Nelson+Pass+lecturing+at+the+Burning+Amp

His products are mostly marketing BS IMO. All those super expensive amplifiers with inferior specs for a reason of being feedback free  . And those were not some tube amps where this would be understandable, but amplifiers consisting from transistors.

[coppice]

All those super expensive amplifiers with inferior specs for a reason of being feedback free  . And those were not some tube amps where this would be understandable, but amplifiers consisting from transistors.

Poorly thought out feedback scheme were the cause of most of the horrible transient performance issues in amps 40 years ago, so its an obviously sound marketing ploy to go to the opposite extreme and say all feedback schemes must be bad. Its dumb, but most potential customers aren't really in a good position to make sense of more subtle arguments. Its like trying to get the public to buy into the idea of a balanced diet, rather than the latest extreme diet fad. The rational argument isn't very profitable. 

[vk6zgo]

The audio amplifier is a problem which was solved over 40 years ago.

Actually 40 years ago (mid 70s) is when a lot of audio amplifier problems were being created. That was the era of 1MHz bandwidth audio amps, with masses of negative feedback, and bizarre transient performance. It was the mid to late 80s before the industry settled down to more sane designs, with proper testing of transient performance.

More recently the move to switch mode amps, to allow things like compact and powerful 7.1 designs, created its own performance issues. Again, most of this was due to a focus on static testing, and too little transient testing. This is only now settling down.

I think the Idea of very wide bandwidth audio amplifiers had its origin in the tube era.

An amplifier with a fairly large amount of negative feedback needed to extend the point at which the feedback changed to positive to well above the normal audio spectrum.
The Achilles heel of tube amps was always the output transformer.
A lousy transformer was more likely to bring the point of phase rotation too close to the required audio frequency range.

It seems the iPad thought I was talking about Football.
"Offside" indeed! Aaaaarrrrrgggghhhhh!   

[Audioguru]

Do you have enough hearing?
Have you tested your hearing?
How old are you ? Me, for example, I have more than 65a and I do not allow myself to judge the acoustic quality of an amplifier because at my age, we do not hear beyond 12 Khz.

Unlike you, I am a music lover. When I became 69 years old I thought that people mumbled and radio and TV engineers were not aware of their terrible sound. I went to a free hearing test and it showed that my severe high frequencies hearing loss was normal for my age so they programmed a hearing aid for me to try. I couldn't stand it! Later I went to another free hearing test and it was the same results as the other test. They set up hearing aids from a different manufacturer with 20% high frequencies boost and I liked it. 2 weeks later they boosted it some more and after 2 more weeks they gave me a completely flat frequency response so that my hearing with the hearing aids is the same as when I was young. Sure they were expensive but they changed my life and are worth it. They also have features that normal hearing cannot do like a setting (each hearing aid has a push button) for extra sensitivity and I can hear people talking far way. They have an audio compressor so that nothing is too loud. They have a muting setting and have a setting that I use in noisy malls and restaurants that has noise reduction. They are directional: front, back, left and right and any combination of them.
I do not understand why old people go around with poor hearing.

Also vision. I became blind with cataracts so I had the bad lenses in my eyes removed and replaced with custom synthetic lenses. Now my vision is better than when I was young and I do not need glasses anymore. I do not understand why people go around .....

Also my heart. I had a heart attack, nearly died so they fixed my arteries. Now I am strong, exercise a lot and feel like I am young again but I look like my age of 72. I do not understand why people .....

I can hear when a sound system has distortion more than 0.1%, has frequency response problems and has noise. Some cheap systems are much worse than Sony and some expensive systems look expensive but sound bad. Some systems that are not cheap but not expensive sound fantastic. Some expensive speakers sound bad and some reasonably priced speakers sound good. Cheap speakers always sound cheap.   

[tszaboo]

And then there's Nelson Pass... He must be one of the oldest amp designers on the planet.
https://www.youtube.com/results?search_query=Nelson+Pass+lecturing+at+the+Burning+Amp

His products are mostly marketing BS IMO. All those super expensive amplifiers with inferior specs for a reason of being feedback free  . And those were not some tube amps where this would be understandable, but amplifiers consisting from transistors.

I got the impression, that he has no idea what he is doing. It is more an art, than real design. Like "look, i've connected a transistor the wrong way, and it still acgs like an amplifier. Lets connect two dozen of this in parallel, and sell it.
I mean look at this:

You know why it works? Because he puts both of them on the same heatsink, right around when the entire house is 32 degrees warm, they self bias themselves, then, maybe we get some output. Variance from circuit to circuit is probably triple digit percentage.

[Circlotron]

they boosted it some more and after 2 more weeks they gave me a completely flat frequency response so that my hearing with the hearing aids is the same as when I was young. <snip> I can hear when a sound system has distortion more than 0.1%, has frequency response problems and has noise.

I wonder if anyone has ever reviewed hearing aids as to which is the better for hifi listening?

[BrianHG]

In amp, and speaker choice, as for listening and evaluating, unless you have medical hearing loss, many of us can tell the difference, it's just that we don't know how to do so, so, we end up buying what pleases us most.

Now, for that truly very few (avoiding audio foolery garbage), since you don't know the what original instruments supposed to sound like, here is a good method to judge, though you require both the amp and speaker in the equation:

Pick a properly uncompressed studio recorded song with natural vocals without reverb or echo added.  If the vocalist doesn't sound like the are there in front of you, not a vocalist on a mic and speaker, I mean there, a physical human being, without a microphone, no speakers, a presence/essence you can feel in the room with you.   At all volume settings.  Be honest with yourself here, you should always be comparing what you hear to real life, NEVER compare hardware A to hardware B.    Do this right and you picked winning hardware.  Affordable solutions to this refinement do exist, however, it takes someone experienced in the business, with access and tests of many hardware and they are not out to rip you off to help you find such quality equipment.

Personally, It was recommended to me to purchase a Belles OCM 500 amp.  I happy and will never will sell it.  Though rated 0.1hz to 20Khz, I measured mine flat to 100KHz at full power.  250w/channel into 8 ohm, safe driving full load into 4 ohm.   Some come equipped as mono-blocks with 1kw output peak.  It is built like a tank and I don't expect it to ever die.

A used one exists here:
http://www.canuckaudiomart.com/details/649201738-belles-ocm-500-soloist-amplifier/
A FN steal at 600$ cdn.

Some finer specs...
http://www.diyaudio.com/forums/swap-meet/205903-fs-ocm-500-david-belles-200wpc-amp-beast.html

Darn, if it weren't for the shipping and that I'm lacking a pre-amp with balanced outputs, (it weighs like a concrete cinder block), I would buy this one and use it with mine as 2x 1Kw mono blocks...

[Beamin]

Nowadays they make Class-D amplifiers with a single chip (digial input) 100+W output and <0.01% THD+N.  I dont even understand why there are amplifiers anymore. Seems so pointless. I believe that good quality active speakers are the way to go.

You need WAY more then just a chip to make good sound. Try driving some 100 watt speakers off a chip. The chip might be able to handle ear buds but not any sized speakers. They keep making amplifiers because you NEED them. How could a single chip handle 100 watts of clean power and still be under its limits to avoid clipping or blowing up for that matter?

Unless you are being sarcastic.

The reason tubes are still used (in preamps) is because they introduce an overtone that creates a warm sound. So they are actually creating distortion but wanted distortion.

I can hear the difference in 0.8THD and 0.03% with decent speakers. I don't think most people could though. I stay away from anything over 0.1% THD because you are not getting the full benefit of your speakers.

Now I'm going to finish reading this thread. Just had to comment when I read this.

[Beamin]

For me, what really makes the difference is not the amplifier but the speakers.
An experienced music lover can only discern distortions greater than 3 or 5%.
A speaker produces a distortion of at least 1%, often 2%.
So, do not tell me that a 0.1% distortion of an amplifier makes any difference.
Moreover, paradoxically, it is the tube amplifiers that have the highest rate of distortion that are considered to have the best sound.

A comprehensive and very interesting study of the speakers was made by G. A. Briggs, one of the founders of the British firm Wharfedale, in his book loudspeakers.

A big technical difference between tube and transistor amplifiers is the damping factor ... that may partly explain the difference in sound of a tube amp.

My personnal preference: I have a Marantz 2285B receiver and a Sansui AU-5500 amplifier. (I think the AU-5500 and AU-6600 are the best Sansui)

I have a Marantz amp I use from the 1990's that is 0.03% THD that is ratted at 50 watts. Hook that up to your best speakers then hook up a Sony 100 watt amp you bought at best buy. I can guarantee you there is a difference to be heard. I myself can't tell anything much better then that.

What interesting is I herd a super audio CD being played over a 2000$ amp through some $3000 speakers (The ones with a single woofer and that strange grid material for the mid and tweeters at a) HIFI shop. The SACD actually sounded worse and tinny because it reveals the limitations of things. I was very surprised at the result.
Do this test:

[Beamin]

Also:

I didn't mention speakers because they are not part of my question. And personally I already have good speakers although to get the bass out of them you need a large amp and to mess with the EQ's.

I still don't have any real answers as to what makes the amp "better" as in when it is paired with very good speakers what technically makes a Marantz sound so much better then a "Sherwood" or "Jensen" or insert shitty brand Walmart amp here?

So I am still leaning towards components with both precise and accurate values as well as an amp design where the signal is well below the "clipping " range with large filter caps.

Here is a very easy way to tell if an amp will sound good or not when I worked in an electronics store as a kid: Pick up the amp; is one side or corner of it really heavy? If yes that because it has a great big transformer in it and all the cheap amps feel light. Transformers are full of copper which costs a lot of money. Probably the most expensive part of a cheap amp and probably tied with the cost of transistor pairs with the build cost of an expensive amp.

One last question : For the cable that connects my dvd player to the amp through the 47KHz digital connection should I go with the 300$ Kevlar insulation or the 400$ Teflon insulated cable?

That was when I first discovered monster cable was full of shit: a 50$ "digital signal low loss high quality "cable for the PCM link. You can literally use two pieces of old telephone wire and get the EXACT same sound as their 50$ cable. A low frequency digital signal makes no difference for a short length or even long length of cable. 

[BrianHG]

Price of components does not equate proper sound as noted in the above post.
Total THD amp ratings usually are specked out with a dummy 8 ohm resistive load, not an inductive speaker with unpredictable cable length.  It is easy possible to get a better sound amp with 0.5% distortion than one with 0.01% distortion.  That 0.5% error may just be a little linearity at the extreme voltage swing, but, may be that amp keeps a perfect predictive curve with any mix of source signal frequency and a speaker who's impedance isn't linear over the spectrum with some nasty kick back current spikes from the woofer at a few undesirable l.ow frequencies while your so called 0.01% distortion amp, which give you that figure into an 8 ohm resistor wired right at the rear of the amp with controlled source signals would otherwise oscillate and give a tinny like sound, or damped out low frequencies under real world random source and speaker circumstances.

A better designed amp, even with a lower quality distortion rating may better deal with the real world unpredictable circumstances.  Don't be fooled by those who say they can hear the difference between a 0.1% distortion  amp and a 0.01% distortion amp, it's not the difference in distortion they are hearing.  It's all the other characteristic differences between the 2 amp, not a fine linearity signal error.

[BrianHG]

Don't fall for speaker cable BS.  Unless you are willing to pay for 99% pure silver cables for the lower impedance, just buy oxygen free 16 gauge household solid core wire & make sure your left and right speaker wire length and impedance match.

The only additional + is if you have 2 feeds coming from your amp on each channel to a speaker which has separate inputs for the woofer and mid/tweeter.

If you want quality and cheap readily available alternative, use CAT5/6 network cable.  For up to 75 watts RMS, at each end tie all the whites together at the - and all of the colored wires together as the +.  For up to 200 watts RMS, use 2 network cables, 1 cable, all conductors merged as a + and a second as a -.  Twist the 2 network cables around each other generating 1 gigantic twisted pair.  You will get excellent results.

[Zero999]

Don't fall for speaker cable BS.  Unless you are willing to pay for 99% pure silver cables for the lower impedance, just buy oxygen free 16 gauge household solid core wire & make sure your left and right speaker wire length and impedance match.

Impedance match? Not necessary for audio cables and differences in length of cable between the channels won't matter.

Also I believe oxygen free cable is marketing BS, just use ordinary cable.

Nowadays they make Class-D amplifiers with a single chip (digial input) 100+W output and <0.01% THD+N.  I dont even understand why there are amplifiers anymore. Seems so pointless. I believe that good quality active speakers are the way to go.

You need WAY more then just a chip to make good sound. Try driving some 100 watt speakers off a chip. The chip might be able to handle ear buds but not any sized speakers.

That is BS. Any amplifier will be able to handle 100W speakers, providing it is designed to drive the impedance of the speakers. For example, if the speakers are 8 Ohm, then a 10W amplifier will be able to drive them, with no problems.

You're right about needing more than just a chip to sound good. You need decent speakers, which are much more important than the amplifier.

How could a single chip handle 100 watts of clean power and still be under its limits to avoid clipping or blowing up for that matter?

Easily. A class D amplifier can handle more power than a class AB amplifier, given the same amount of silicon and heatsinking, because it's much more efficient, thus produces less heat. Clipping is dependant on the supply voltage and load impedance. The good thing about class D is the voltage loss in the output stage is lower than class AB, so for the same supply voltage, the output level can be higher, without distortion.

I can hear the difference in 0.8THD and 0.03% with decent speakers. I don't think most people could though. I stay away from anything over 0.1% THD because you are not getting the full benefit of your speakers.

I very much doubt that. With a decent pair of headphones, you stand a chance, but not much, especially at your age.

Here is a very easy way to tell if an amp will sound good or not when I worked in an electronics store as a kid: Pick up the amp; is one side or corner of it really heavy? If yes that because it has a great big transformer in it and all the cheap amps feel light. Transformers are full of copper which costs a lot of money. Probably the most expensive part of a cheap amp and probably tied with the cost of transistor pairs with the build cost of an expensive amp.

That might have been true for older amplifier designs, which still use a big lump of iron to convert the mains voltage to DC, but not in modern designs, which use a switched mode power supply.

[hamster_nz]

You need WAY more then just a chip to make good sound. Try driving some 100 watt speakers off a chip. The chip might be able to handle ear buds but not any sized speakers. They keep making amplifiers because you NEED them. How could a single chip handle 100 watts of clean power and still be under its limits to avoid clipping or blowing up for that matter?

Unless you are being sarcastic.

I know it isn't a single chip but: http://www.altronics.com.au/p/k5181-classic-250w-class-d-audio-amplifier-kit/

PCB is about the size of a paperback. (117 x 167mm).

From what I can remember about reading the magazine article a few years ago the specs were pretty good - as good or better than a similar rated high quality discrete amp. Somebody here will most likely have the magazine article and can provide numbers.... e.g.  10Hz - 20kHz +/-1dB, THD 0.01%

[oldway]

Most speakers give around 3% distortion measured 468-weighted 'distortion residue' reducing slightly at low levels. Electrostatic speakers can have lower harmonic distortion, but suffer higher intermodulation distortion. 3% distortion residue corresponds to 1 or 2% Total harmonic distortion. Professional monitors may maintain modest distortion up to around 110 dB SPL at 1 m, but almost all domestic speaker systems distort badly above 100 dB SPL.

https://en.wikipedia.org/wiki/Loudspeaker_measurement#Distortion_measurement

[BrianHG]

Impedance match? Not necessary for audio cables and differences in length of cable between the channels won't matter.

Hun? Non matched left and right impedance speaker cables.  Say you total Left wire is 0.3 Ohm and your Right's total is 0.6 Ohm, with 4 ohm speaker load on each, wont the left be a little louder than the right?

I don't buy that.

[RobK_NL]

Say you total Left wire is 0.3 Ohm and your Right's total is 0.6 Ohm

That 0.3 Ohm difference equates to 10 meters of 1.5mm² cable. That's more than what most people would have in total.