[nathanm]

By design a hifi amp probably shouldn't have the same tonal variety that you want in an instrument or even an instrument amplifier. The problem is, they keep making prettier ones and making me want to buy one even though I've got perfectly nice ones that do the same damn job just fine.  Damn them!

It seems that ears are much cruder sense organs compared to eyes.  For instance, there's plenty of people who think that all amps sound the same, but you'll find rare few who claim that all amplifiers LOOK the same.

[AKSA]

I do not agree.  All amps sound different, but unless you have the chance to AB them, and know what you are listening for, it's not always obvious.

If it's really bad, there is no vitality at all to the music - flat, and uninspiring.  It is merely an emotionless, mechanical rendition, like a bad player piano....

I think the ear is very sensitive, particularly on vocals and certain percussive sounds.

Specs won't show this.  An SET with 4% THD sounds somehow 'better' than a Phase Linear 400, yet the PL has only 0.1% distortion.  Could it be we are measuring something which is obvious to a distortion meter, but almost wholely unrelated to the subjective experience of listening?

The deficiencies of an amp are not apparent until you hear another working the same source, material, cables and speakers.  Then you can pick the differences.  Soundstage issues are not subtle;  with a good recording and a good amp, particularly on choral works, you can pick out image (notably soundfield) very easily.  Another excellent test is clapping.  It prescribes the soundfield very accurately.

The 'feel' of your present auto is so much more apparent when you take a late model 330i Beemer for a test drive.  Then you know how good it can be.  Something very similar happens with amps, and often manifests in the engagement of the performance, whether you connect emotionally with the music.  By this I mean spontaneous grinning, tapping of feet, a feeling of being part of it.  A bad amp can't do this, at least to nothing like the same degree.

With a good amp, even an ordinary speaker sounds pretty good.  The reverse is not true.

This is MY opinion only.  Many will disagree;  that's their prerogative.

Cheers,

Hugh

[imassarano]

Well, I would like to mention an experience that I had at a hi-fi shop in the mid '70s, when I was first starting off in hi-fi. I had booked a demo, and was waiting while somebody was a/b'ing a couple of budget speakers through a decent budget amp. I wasn't paying too much attention while listening in, as both of the speakers sounded poor, and I didn't notice any difference, until the assistant changed the amp to a Luxman, and man what a difference!!   One speaker really came to life and was now clearly better than the other.

[JohninCR]

I think it's a silly debate.  Of course amps can sound different.  You just have to understand what to listen for to hear the differences.  Different amps will cause the same speakers to behave differently due to the amps' damping factor, frequency response, orders of harmonic distortion even at small levels, etc.  These differences can be much more than subtle.  You also have the tube vs SS comparison where the tubes add something to the signal.  While often pleasing to the ear, it's definitely a difference because things are added to the original and must create a difference.  Another factor seldom discussed is cross talk between channels (mute one channel, disconnect the other channel's speaker and crank up the volume and what you hear out of the muted channel has to affect a normal presentation however subtle).  This invariably affects the presentation.  Cheever's work gives some good insight into why amps can and do sound different, since commonly accepted THD measurements are insufficient in telling you why amps can and do sound different to the trained ear.

On the other hand, I have to laugh at the camp that inevitably uses the flowery and meaningless language to describe the differences heard and they require long periods of listening to each to hear a difference.  Our audio memory is quite short in duration, so a meaningful comparison must include a switch done on the fly, immediate and seamless.  Otherwise you're left with wanting/expecting to hear a difference.  This is the only audible justification between a $10k amp and a good sub $1k amp and the long listening sessions for comparison are required to justify the price differential for the buyers of expensive amps, because psycho acoustics have to kick in.

Thats my 2 cents.

[JoshK]

I am not really interested in discussing whether amps all sound the same or not, as that is a bit pointless if you believe in this hobby.  However, it does bring up an underlying issue which some have touched upon.  That is the measurements we still use.

For the life of me, I cannot understand why we (the audiophile community, not the mass market) still insist on stating THD.  IIRC, the western electric engineers in the 30's or at least 40's knew about higher order harmonics vs lower ones. Someone else who's name escapes me but starts with K wrote about better measures rather authoritatively. More recent work by Geddes has finally put the nail in the coffin to the THD measure and added real evidence to the correlation of better measures with hearing which place increasing emphasis/penalty with rising order. 

With modern computers and equiptment I think measuring higher orders up to N (say 9 or whatever's clever) is a non-issue.  Pick a measure, be it the Geddes, square of the order or factorial weighting and report that.  If some of the more progressive manufacturers like Hugh, Frank, et al started actually quoting these and we the community started putting pressure on reviewers (who measure) to start using them and other hi-end companies to start, I think at least in our own world we can have something more meaningful then the pointless THD which every brushes off anyway. 

I was thinking about this last night when I got my new issue of AudioXpress and was skimming through a measurement section on the Outlaw amp.  I was baffled enough to consider writing to AX to plead with them to atleast add it to the list of things they measure.  If we are going to bother with measuring THD, IIM, etc, why not one that the audio engineering community has more or less accepted long ago?

[Dan Kolton]

Frank,

Thanks for the explanation of what the problem is with A/B/X tests.  I'm sure you've said it before, and I just missed it.

[nathanm]

I do not agree.  All amps sound different, but unless you have the chance to AB them, and know what you are listening for, it's not always obvious.

Yep, that was my point.  The sound difference is subtle and requires explanation by another person whereas no one needs to be trained to tell object A is not the same as object B with their eyes.  I would not be able to convince my non-audiophile friends that a song played twice through two different amps in fact sounds different without first telling them what to listen for.  (and assuming the levels were matched)  The audiophile thing is usually too subtle for the average joe which is why I say that ears seem cruder.  Yes, they will be able to tell, but not without prior training and instruction in most cases.  This has been my experience.  Unless you are "into" this stuff most people filter out the electronics factor.  To me it almost seems like a good thing, because these people enjoy Song A no matter what its played on. Unlearning the hifi heightened senses factor is something I sort of wish I could overcome.  It would be nice if I didn't think my car amp sounded dead awful for instance.  Heh!

[Wayner]

Every speaker sounds different because they are all designed differently using varying crossover points, slops, cabinents, drivers, coils and resistors, even the weather can affect their performance (temperature, humidity, etc).......Every amp sounds different because they use varying designs, components, topography, power supplies, power devices..........So when you connect an amplifier to a speaker, you get a marriage of an elctrical motor power supply driving a complex motor(s) assembly that reacts to different loads at different frequencies with different harmonics requiring different amounts of power on a micro-seconds demand. I have seven amplifiers and seven set of speakers that probably can produce 49 different sounds. I not trying to brag about how many pieces of equipment I own, but I've spent alot of time trying to get the right couples (or 3-somes) together.....and there have been quite a few divorces as well. In short, IMP, the marriage of amplifier to speaker is the real question, not how an amplifier "sounds" and therefore the question of all amplifiers sounding the same cannot have any other conclusion: They all sound different because they all react to complex speaker loads differently.

[john1970]

This afternoon I just A/B compared a Bryston 6B SST (three channel version of the 4B SST) to my NAD C372 (its predecessor was a Stereophile Class C component) using the NAD's preamp section. 

The Bryston had the following improvements:

1) a cleaner and more detailed midrange  You might not notice this without the A/B test, but it was very noticeable on Windham Hill A Winter's Solstice, Vol. 5 track 16.  Switching to a Bryston Preamp (Bryston SP1.7) gave a slight improvement in this area.  However, the majority of the improvement came by switching the amp and NOT the preamp

2) deeper and better defined bass.  Very noticeable and could not detect any difference in this area when preamp sections were switched.

It is very true that not all amps sound the same.   

Just my observations,

John

[G Georgopoulos]

certainly not, speakers dont sound the same, sources are not all equal etc
it all comes down to proper analysis of why they sound different one factor
would be quality of design the other quality of materials and all do have a
role to play in the final sound and specification

cheers

[David Ellis]

This afternoon I just A/B compared a Bryston 6B SST

My first decent amplifier was a Bryston 3B-ST.  It was indeed good.  That was @7 years ago, and increasingly better amplifiers have displaced the Bryston since then.

As you system improves a similar comparison between a Bryston and the gear from Bill Baker, Hugh Dean, or Frank VanAlstine will net similar findings.  Common commercial folks can't compete with these guys.

I recently purchased an unmodified Cary 572 thinking that it should sound fairly decent at lower volume levels.  It's a Single Ended Triode with no feedback and @ 20wpc.  While the instruments were in proper balance, the sound quality was EXTREMELY mediocre.  I am being kind.  While the Cary 572 is a very respectable piece of hifi gear in commercial circles, it is not on par with the better/modified amplifiers from the gentlemen mentioned herein. 

I am sure you will have some desire to experiment and hear things for yourself.  I certainly do.  In your experimentation, I highly suggest you get an amplifier from one of these gents.

Dave

[weirdo]

Its an interesting debate. I have only had low end vintage power/pre amps and a whole bunch of receivers prior to getting my AVA gear.One of them was tube.  Of all the receivers I have had, a 40 watt scott tube receiver from 1963 was the best sounding. I did a A/B with the AVA gear and I concluded that the AVA gear was more detailed... Noticeably ...but it should have been for 4 times the dough. Having said that, my little experiment caused me to rethink the value of speaker type and speaker placement, which are now above electronics and source quality as the most important factors in my system. The reason I got the AVA gear is because it looks like it can last. And it will. Another extremely important and sometimes ignored factor. A good debate would be  " do all ams last the same!

[jqp]

We will forgive you based on your low number of posts, but this is patently absurd. You mean to say that someone is claiming that my Yamaha receiver is indistinguishable from my monoblock amps? There is no way that I can't tell the difference.

Can I set up a test between amps where you can't pick one over the other? Sure if I pick the amps to compare. Big difference.

Audio memory is less reliable than visual memory, but it is not that bad.

Similar amps can sound very similar, all amps do not sound the same.

[chadh]

When "coke zero" came on the market, my wife challenged me to a taste test.  If I could not pick the real coke over  the coke zero in a series of blind experiments, then I would have to give up drinking the coke in favour of coke zero.  She gave me three pairs of identical glasses, each glass half filled with either coke or coke zero.  I tasted from the first two glasses:  these were obviously different drinks.  I tasted from the second two glasses:  these were obviously not the same drink either.  And tasting from the third pair of glasses, I could also discern clear differences.  The problem was that, on two of the three tests, the drink I picked as the real coke was in fact coke zero.

Does this test suggest that I perceived no difference between the drinks?  Or simply that my palate wasn't sufficiently sophisticated to consistently identify what those differences were?  I know that my desire was to select the drink in each test that tasted best.  But in the tests, neither drink really tasted better than the other - they just tasted differently.  But in the end, I couldn't identify precisely what the differences were.

It strikes me that a failure consistently to pick amp A from amp B in a double blind test couldn't possibly come close to establishing that there is no difference between them.  But it may very well be an indication that the person who cannot identify the difference consistently probably shouldn't really care which amp (s)he has.  For that reason, I now drink coke zero.

Chad

[WEEZ]

I agree with BrianM almost 100%.

Where I differ (slightly) is 1) power; and 2) timbre.

To clarify:

1) Power. Provided that the amplifier(s) being evaluated have sufficient power to drive the speakers to a realistic level without clipping; power in and of itself should not be audible.

2) Timbre. I find this to be even more obvious than soundstaging...at least at first. Over time, I would agree with BrianM, however.

I am not trying to pick nits, here. Good post.

WEEZ

[WEEZ]

Thanks for the clarification. I don't disagree.....

WEEZ!

[Feanor]

Do all amps sound the same?

In the last 3.5 years I have listened to the following in my own system:

• Phase Linear 400 power amp with Apt Holman preamp
• Harmon Kardon 330A receiver, power section with Apt Holman preamp
• Marantz 205 power amp with Apt Holman preamp
• Bel Canto eVo2i integrated
• Bel Canto eVo2i as power amp with Apt Holman preamp
• Bel Canto eVo2i as power amp with McIntosh C712 preamp
• Bel Canto eVo2i as power amp with Adcom GPF-750 preamp, pass and active modes
• Monarcy SM-70 Pro, pair with Adcom GPF-750 preamp, passive and active modes
• Marantz 2252B receiver

The differences among the amps were clear to me.  The differences among the preamps much less clear, though the Adcom is marginally the most detailed and cleanest, especially in passive mode.

Could I pass an A/B/X test?  As these tests are usually administered, I will allow that I might not pass -- however I am convinced that amps do not all sound the same.

[MaxCast]

Talk about a manufacturer voicing an amp, or any component for that matter.  There is someone somewhere making the call on the final design.  He is listening through a source, preamp, speakers, his ear and room....with his own thought on how it should sound.  Lots of variables and subjective preferences going on.

[Dan Kolton]

"Could I pass an A/B/X test?  As these tests are usually administered, I will allow that I might not pass -- however I am convinced that amps do not all sound the same."

Frank explained a while back why ABX testing with the ABX Box results in each amp feeding crud back through the other one, so you probably won't hear a difference.
 

[WEEZ]

I agree, an A/B/X test is fruitless.

Comparing two different amps over time, however, will reveal differences. As the amps being compared get better and better; it becomes harder to discern differences. BrianM referred to soundstage; I think that is one of the characteristics to listen for. I listen for that as well as timbre...the better amp will allow for a more natural sound. The more I think about it, those two factors are inter-related. (sort-of  )

A good amplifier will be transparant to the source; low in coloration; yet harmonically complete and relaxed at the same time. No small feat.

WEEZ