I know many of you here believe that some amps simply sound better than others - I agree to an extent. But after taking out the hiss and pop factors that cheap amps have, it is exceedingly hard to tell the difference between any two amps putting out the same power levels. Graphs might show a flatter response, lower certain-order harmonic and IM distortions and such, but the human ear will never hear it.

Yep, I am willing to come into a forum devoted to sq and tell everyone that there is no way any of you could consistently tell the difference between a JL slash amp, an alpine PDX, and a brax amp all driving the same speakers, level matched, in a double blind test, even being able to choose the listening environment and the speakers!!!

If you wish to challenge this claim, please read the entirety of this page Amp compare and discuss. Hey, I was convinced amps made a huge sonic difference too. Turns out I was wrong, and hundreds of others have been proven wrong too. Not to worry, the more expensive amps are still worthwhile, because

* They usually have more power on tap than stated
* They tend to last a long time
* They don't overheat under normal use
* They don't pop or hiss, or run at a DC offset (BAD for speakers)
* They look cool
* They have a lot of cool features (HP/LP filters, etc)

but no high end amp (even one costing $4000) SOUNDS any better than another (which might cost $600). If you REALLY feel offended, PM me, go take the plane trip and do the challenge, you will be many many dollars up if you succeed, even if you have a ball while you're over there! $10,000 is a lot of money, and you only have to pick which amp is which out of 12 tests!

And now I dodge the bullets...

While I agree with you to some extent, I think most people will say that certain brand amps have a 'warmer tone' and some are different again etc. So I don't know if people here would say this amp is 'better' than another one (on listening alone) but the features and reliability might make it the 'better' amp more than the characteristic sound of any given brand... I don't think it's all a placebo effect, put it that way!

I'm not reading through the link, mainly because I am too tired, but this seems a lot like the Richard Clark test, and as such if you run a search on here you'll find that it's been discussed

Not shooting down the thread, more just pointing out a similar thread has been started. Then again, this might be a different thing, and if so disregard this reply heh.

Edit - I lied, I quickly checked it out, and it is the RC test like I suspected. It has been discussed, no matter what, there will be some that will argue against what has been stated.

Yeah, sorry guys, I did find the old thread, but rather than bring up a thread from 5 years ago, I thought I might re-open the can of worms. Most of my personal reason for doing so is the alpine PDX amps, which so many "audiophile snobs" (I kinda consider myself one btw) seem to think can't sound any good because they are full range class D. But since the world final of MECA was won by a person using them last year, I would love to see some of these people take the challenge.

The "warmer tone" people often talk about is a slight rolloff of the high frequencies (tube amps and those meant to sound like them have this) that takes the apparent edge off the treble. It is not really to do with a "better sq amp".

In the other thread it was mentioned that no car ever won an sq comp with cheap amps. I've got some ideas why that might be.

* Judges know what amps are being used. Psychoacoustics could be a major factor.
* Cheap amps *can* hiss, ruining imaging. Lowers the score a bit
* Cheap amps tend to have higher THD levels at the rated RMS power. Sometimes it could be enough to be audible if amps are being pushed during judging.
* Cheap amps often have DC offset problems, which will mean speakers may reach their Xmax in one direction and clip when both the amp and speakers are running below rated RMS power levels.

Apart from these factors, I would be in favor of suggesting that no SQ amp is "better SOUNDING" than another. Mind you, try matching HP/LP filters when A/B'ing amps. I think this is where a lot of "sonic difference" might be found, in which case, still doesn't prove RC wrong.

It's all about listening preference though I would've thought... No better 'sound quality' between amps - maybe just more popular 'sound'?

Not sure exactly what you mean. Amplifiers put out no sound out all. They output an electrical signal to the speakers. It's the speakers that make the sound. Only a REALLY bad amp has any "sound"

I can accept that people may have varying opinions on amps and that there may be slight audible differences between different products. The only thing that frustrates me is when I see someone classify good amps as having an 'asian sound' which I guess suggests that the amps will impart some sort of tinny quality on the speakers. Can someone explain to me exactly what causes this mystery 'asian sound' some amps (eg. PDX) are claimed to have as opposed to their European and American counterparts anyway? I'm more than willing to accept some amps are more suitable for different applications than others but when I see people that are so set in their opinion that they start to misrepresent other products then thats a shame.

I hear you. I really do. This is the sort of garbage that RC's test was designed to eliminate. Perhaps "asian sound" means, "I have no idea how to set up an amp, it's all *asian* to me"? Not OVERLY likely, but hey, weirder things have, do and will continue to happen.

The point of the RC test is that all things being equal one amp sounds a lot like another.

However, in the real world you don't always listen until ideal conditions, people push amps well outside these constraints, then you appreciate the benefits of a high end amp.

Phil

No its not Phil. Not even close.

The Point of the Richard Clark test is to indicate that what can be measured, can be cheaply replicated externally to the amp. Amplifiers DO have sonic signatures, but these signatures exist within the realms of gain/power/frequency response/output impedance/noise and distortion. Fortunately, most scientists are clever people, and know that to PROVE one thing is making a change, you NEED to control everything else so it doesnt affect. Hence his 'rules'.

Since 'sound' of an amp is easily measured and understood, we can replicate it with other devices. You'd be surprised how easy it is to make an Audison Thesis sound like a Jaycar (easy also = cheap).

This has been discussed only late last year with quite a bit of depth. Recommend some of you read up before making wild statements.

http://www.mobileelectronics.com.au/forums...l=richard+clark

Also the sound of a Tube amp DOESNT come from rolling off the highs. Most decent tube amps have a fairly flat FR. It comes from lowering the output impedance to ridiculously low levels.

Simply put, you never buy an amplifier based on its sound.

Well there you have it folks.

I beg to differ, from RC test:

Amplifier Comparison Test Conditions

1. Amplifier gain controls - of both channels - are matched to within +- .05 dB.

2. Speaker wires on both amps are properly wired with respect to polarity. (+ and -)

3. That neither amp has signal phase inversion. If so correction will be made in #2 above.

4. That neither amp is loaded beyond its rated impedance.

5. That all amplifiers with signal processors have those circuits bypassed. This includes bass boost circuits, filters, etc. If frequency tailoring circuits cannot be completely bypassed an equalizer will be inserted in the signal path of one (only one and the listener can decide which) of the amps to compensate for the difference. Compensation will also be made for input and output loading that affects frequency response. Since we are only listening for differences in the sonic signature of circuit topology, the addition of an EQ in one signal path only should make the test even easier.

6. That neither amp exhibits excessive noise (including RFI).

7. That each amp can be properly driven by the test setup. Not normally a problem but it is theoretically a problem.

8. That the L and R channels are not reversed in one amp.

9. That neither amp has excessive physical noise or other indicators that can be observed by the listener.

10. That neither amp has DC OFFSET that causes audible pops when its output is switched.

11. That the channel separation of all amps in the test is at least 30 dB from 20Hz to 20kHz.

Well what is the difference between Asian cars, European cars and American cars? After all the all use metal and have internal combustion engines that work on pretty much the same basis with much of the same componentry??????

Exactly. Any car can drive you down to the shops at 60km/h.

However, some of us want more from our cars.......

Phil

I have listened to many amps, and I know that some do sound the same, but some also sound different.

Well just going off the previous threads, it is clear that the REAL things to look for in "sq" when it comes to buying amps is:

1. Low noise floor (better imaging)
2. Low output impedance (but this can be altered after the amp anyway)
3. No DC offsets (only REALLY bad amps have this anyway)
4. Enough EQ, HP/LP, phase, and whatever else you need to spend no less than 8 hundred hours tuning your car to perfection only to discover that you want to change your front stage to scanspeak/seas and your subs to morel ultimos anyway

What DOESN'T matter is

1. What class you buy. A, A/B, and D (let's not forget ultralinear) are all fine SQ wise (as long as the D transistors have a high enough bandwidth)
2. Whether it has some magical circuitry that lowers 7th order harmonic distortion or rejoins the top and bottom halves of a signal in push-pull A/B together using "perfect symmetry" (sorry JL, I love your amps and use them myself but that is a silly thing to claim)

Still, I say all of this, but if I had billions of dollars I would get somebody to custom build me an amp using no less than 32 matched JJ 300B tubes per side all running in triode mode, single ended class A, with a heat sink the size of texas and 18 carat gold wiring, inputs, and outputs. And that would just be for my tweeters

ummm... why?

sounds like your on your way to taking 10k off richard clark

Phil,

Your not understanding the basics. The rules are there for a very specific reason.

Lets say I take two amplifiers, from two different brands. I put them together and test their sound to determine whether they have a unique sound.

Now I know six variables that influence that said sound. I also know that things like Solid State/Tube, Class, Brand, country of Origin, type of components used etc. etc. DOES NOT affect this sound if they do not influence my original six variables. Marketing (obviously) disagree.

To CONCLUSIVELY prove that ONLY these six variables influence the sound, I need to individually isolate each one, and eliminate its variability, thus leaving only these magical whispers that other people claim can change the sound. Its the basic method of proof in the scientific community.

His rules eliminates all those very variables between the amps. Power is now the same. Gain is now the same. Distortion is now audibly the same. Output Impedance is now the same. Frequency Response is now the same. Noise is also, now the same.

We've just eliminated all the variables which cause an amplifier to sound different (as many of them do). So whats left? Your magical 'class A sounds better then class D', 'Tubes sound different to solid state', 'more expensive amps sound better then cheaper ones' etc. etc.

He used to have $10k on this test. He put his own money forward to prove that when we eliminate those original six variables, you cannot tell any amp from another. Throw in the 100% correct rule (because if its audible, you should be able to hear it every time) and you also remove the 50/50 by chance.

Each of those six variables are actually quite interesting, and is easily demonstrated that with simple common devices (like thin cable, head unit EQ's etc.) we can make a Jaycar sound like a DD if the amp is played within its limits. Sure the DD has more power, but if we will never exceed the limits (and clip) of the Jaycar, then the DD is simply extra power that we'll never use.

That is why, no-one should ever consider 'sound' signature when purchasing amplifiers.

ummm... why not, if i can afford and fit it? I'm sure plenty of "golden ears" are going to "hear" how great it sounds once they see it, and they are hardly going to argue that someone somewhere else has a better amp, now are they?

In all seriousness though, I wouldn't go that far. On an unlimited budget I would simply get something like a brax, helix, audison, Hertz or DLS, but, on a total system budget of less than 10k including some custom work and the labor for the install i'd be (and I am) more than happy with JL, alpine, DD, eclipse etc.

That's exactly what I said:



PS: You mean you're not your.

I think this thread will close if the discussion doesn't get back on topic.

Hmm. Fair enough!! I can see it in the first sentence, but the second, seems way off.

Either way, so long as people understand the statement being made by Richard, and use more common sense when purchasing amplifiers, then I guess we agree

Do amplifiers sound different? Yes!

Should you purchase an amplifier based on its sound? No!!

It's a common misconception that the Audison & Hertz products are expensive or out of the reach of most people.

You do not need a massive budget to afford Audison or Hertz products, there are models that will well and truly compete with the brands you mentioned at similar price points.

exactly! my best guess is that purchasing on sound is more of a HiFi thing than a car audio thing.

why?

because many in hifi dont own an EQ, or understand how different impedence affects speakers. etc etc thats why we have this silly 'cables dont make a difference' arguments.

in car audio, we do use a lot of EQ's and fiddle around with active crossovers.

again. its purely a philosophical argument whether or not someone buys an amp based on sound or not.

The sound of an SQ amp... Or the silence of an SQ amp..

Basically if you want to decide if an amp is has "good SQ" then it needs to be decided at how well the amp can be a hidden link i.e. not having a sonic signature and changing the way the source sounds.
Of course if an amp does have a sonic signature and changes the way the source sounds, this doesn't mean it sounds bad it may sound better to some peoples ears.

br85 you mention a PDX is an SQ amp, to my ears its not - but thats me.

Well I better run off to Strathfield and buy a heap of boss audio amps to run my system.

Thanks guys you have saved me a heap of money .


Cheers

I think it's purely a matter of buying something of a reasonable quality around 100db S/N ratio, good channel seperation (if they list it) rated power at low THD levels etc.. . You don't need to spend mega big bucks to get quality either, Alpine, Audison, Boston, AudioSystem, and many other amps that fall in the price ranges of those are going to be good reliable power. And for me personally I always try to buy more power then I need as this will give your amps that little bit of breathing space, aka headroom.

A good example of quality is the old Cousic 505DR (Design Referance) it's rated at 2 x 50wrms (plenty for tweeters) @ 4 ohms and .05% THD and stable into 2 ohms, the equivelant new Coustic is the C100 which does 2 x 50wrms aswell but it's rated at 1% THD, so the new one is rated at a 20x higher THD rate, it's pretty obvious which one is a better amp, I know which one I'd rather buy (and did).

I mention that the PDX is an sq amp, because (according to Mcleoud, 2nd place in last years MECA world comp) the WINNER of the MECA international competition was running ALL PDX amps. Judges seem to think they didn't do anything "not sq" enough to stop the car from winning first place...

I will check my source though. I've been wrong before.

If you are saying that they are "fine SQ wise" I would agree. But if you are saying that it doesn't matter, I can't agree with that. It DEFINITELY matters, anybody who thinks otherwise is welcome to bring an amp over and listen to my home setup. Have you listened to these amps?



Why is it silly? You don't believe in crossover distortion? You don't believe in negative feedback?

I meant it doesn't matter in that a quality amp of each class will "sound" GREAT (amps shouldn't "make sound", that's the speakers job ). Obviously price, power handling, noise factors etc. are other issues one needs to consider when choosing amp classes, but sq shouldn't *really* come into it.

I do, and I do, but it is silly to market it in such a way that makes your amp seem like it is doing something that every other amp is not. ALL quality A/B class amps have SUPERB (especially nowadays) signal resolving, and when you're talking about incredibly low amounts of crossover distortion compared to double digit harmonic distortion introduced by speakers, you're well into the realm of the inaudible.

I cant tell if that's sarcasm or serious, but one thing I will say is this: If you judge your amplifiers based on Sound, and you have the basic tuning tools available in almost every headunit these days, then a Boss Audio Amp will do you fine.

If you care more about those other things, such as reliability, power, distortion etc. etc. then Boss may not be your best choice.

i really really cant be botherd reading though all the rubbish.

RC's test cuts out any form or EQ etc etc.. but who the f*** does that in real life in there car?

so whats the point, test the amps as they are built.

amps are designed with EQ'ing, with tonal differences, this is what makes an amp, yes, amps sound different, yes its cause of all these things.
this is what you are paying for, for engineers to design an amp that sounds pleasing.

Read my original statement. It answers your questions directly.

I whole heartedly agree with the comment that many many people listen with their eyes rather than their ears. I have one of my Rainbow drivers missing from my left door. Its in my bedroom, yet I had a guy the other week say it was the nicest thing he had heard and 'oh those rainbows are awesome' when the only sound emmiting from the left hand side of the car was from the tweeter. Same goes with amps. I'm more in Home Hi-Fi than car audio and in a dead quiet room a/b ing two different amps its hard enough trying to distinguish a difference in tonal character.

On the topic of value amps, they sound different - NOT better. Give me a SS amp with decent headroom any day over an amp that costs an arm and a leg and distorts far too easily but hey it has a "warmer" sound. The problem with a lot of audio things is people tell themselves that the expensive sound is the better sound, rather than what sounds better to them.

Are you saying that all amps sound the same, because amplifier distortion gets drowned out in speaker distortion? Have you ever investigated this for yourself - i.e, have you tried swapping amps around to hear what effect it has on the sound?

Most of the time, the amplifiers are tested as they are built - they are simply gain matched and the LPF/HPF/bass boost are turned off, and they are only matched with an EQ if they can't be turned off.
As per the rules. (and FAQ here)
Most decent quality amplifiers are designed to have a neutral effect on the sound and thus will sound almost identical out of the box.

They can also be driven into clipping provided the difference max power output of both amplifiers is within 10% (at clipping).
EQ or output impedance matching is only used for a handful of amplifiers.

The amplifiers must meet minimum conditions such as:
'That the channel separation of all amps in the test is at least 30 dB from 20Hz to 20kHz.'
'That neither amp has DC OFFSET that causes audible pops when its output is switched.'
'That neither amp has excessive physical noise or other indicators that can be observed by the listener'

It is possible that very cheap amplifiers may have noise issues, poor dynamic range, dc offset (not terribly dangerous to speakers, but very annoying to hear) and thus fail those conditions.

On the point of dynamic range, some manufacturers fudge the measurements by taking full volume measurements, rather than 1w - which means the specifications might not be comparable to other manufacturers and a small amount of hiss may be audible in silent passages.


But as stated in the OP, there are other reasons why you don't go out and buy the cheapest amplifier available - reliability is also a key concern.

I've only done this with a few 12v amps in my ghetto rigged home setup using large computer power supplies. 4 or 5 different A/B class amps and when the gains were matched as close as possible (as well as the HP/LP filters where necessary) it is VERY hard to tell that I'm using a different amp when I switch one out for another. I have not been able to get my hands on enough amps to experiment with different classes at home, but I dare say I'll make the same findings as RC has - amps that measure the same, sound the same.

Can crossover distortion be measured? I'm not sure myself, but since no one has ever passed RC's challenge, and crossover distortion is well and truly allowed in the challenge rules, that the difference that a morsel of crossover distortion makes is not something worth spending hundreds (or even thousands) of extra dollars to avoid. I'm sure those extra dollars could go somewhere else that makes a MAJOR difference that actually can be heard i.e. more deadening/damping, better pods or mounting designs, more expensive drivers, better HU's, exterior tuning units, the list goes on.

From a different viewpoint : is there a reason people should change the way they think about amp sound quality? I can't think of one really... Personally I'm happy to do a bit of listening/testing and make up my own mind rather than take the psychological/mythbusters type approach! That's just me though.

I see what your saying but at the end of the day we're talking about money here. If amps were free we'd all take the gold plated top of the line amps but when the difference in price is in the thousands and while doing a blind test your hard pressed to use your ears and spot the difference under the same conditions, that type of approach isn't too bad an idea.

There's so many models new and secondhand too that are affordable to most people too as you know. When I say affordable I'm thinking under about $500. I don't think people can go too far off track if they stick to reputable brands and get a few opinions. Seems as if we're taking out a link in designing a system if all amps are treated the same.

I chose my amps based on 2 criteria -
1st was reputation, recommendation and specs.
2nd was size - no point buying amps that won't fit in the car.

To me, the JL's were the best fit for both the above criteria

Strange, i've had maybe a dozen different amps in my home setup and I can tell you that the differences between them are pretty obvious. In fact you can hear the difference the moment the first note is played.



Crossover distortion can be measured. On my amp at home, I can set the bias to specify how much of the amp's power is delivered in Class A vs. A/B. The reason the bias control is available is so that I don't burn out the valves by setting the bias too high. But if the bias is set low, Class B cuts in a lot sooner. You can easily hear the difference.

Richard Clark's test is a good example of people misinterpreting the test as proof of a negative.

i think im going to have sex with u.

maybe im a little drunk?

Then perhaps it would be an investment for some of us at mea to send you over to win the challenge!
If it's that obvious, and the amps you are A/B-ing measure the same, you can't lose!!!







But I've got a feeling that when you change amps that filters, output levels and impedance and such are playing a much bigger part in the "sonic signature than you're prepared to admit.

Although, if you are using an RTA to make sure the amps measure the same when you switch, I apologize for making harsh assumptions.

I think all tube amps (that I know of) have bias controls. The main reason for having these is that the plate current is VERY different between tube types, brands, and even from tube to tube from the same batch, the current draw on one can be completely different. Thus, biasing is necessary. Tube preamps also use a tube (usually a 12ax7, 12at7, or 12au7) to invert the phase prior to push/pull amplification (which is necessary for a/b amplification). This phase inverter tube adds another level of inconsistency to the operation of the amp, because without a good balance, the crossover distortion will become quite apparent. Single ended class A needs no PI, and I'm guessing that this is why so many tube freaks rave on about them so much. Modern SS amps do not have anywhere NEAR the phase inversion problems that tube amps "tend" to have. Tubes can be very hot, noisy, inconsistent, expensive and unreliable animals at times. I suppose they do look awfully cool though, all lit up and stuff. At the end of the day I would rather spend all of that extra cash NOT having any added noise in my system, and (in home audio) building bigger and better speaker arrays for my front end.

No offence br85 but you should probably read this line more than once

RC's test doesn't use amplifiers as they are, all variables that will change the sound are taken out - thats why he always wins, he is smart by doing this.
RC himself knows that amps used how they were intended to sound different. Its a fact.

You're all skirting around the facts though.

RC's tests were never about whether amps sound the sound, or whether they have a sonic signature. He knows they do, I know they do, you know they do.

RC's tests were to PROVE that whatever measures the same, sound the same. And that ONLY the six variables mentioned previously, contribute to the sound. AND that we can replicate these six things externally to the amp for cheap.

So why buy expensive?

br85 I indeed do have an RTA showing the frequency response of two different amps in my system.

Click to view attachment

RED line = Cary CAD-211AE amplifier (110W triode push-pull)
CYAN line = Cary CAD-805AE amplifier (50W single-ended triode)
MAGENTA line = bi-amped

The volume for the CAD-805AE was reduced so that the curves could be superimposed and you can see the difference. Notice how closely all 3 curves follow each other? They certainly do measure the same.

However I can tell you that they most certainly do not sound the same. The 805AE is leaner in the midrange but has an extremely clean top end. The 211AE has a big fat midrange and a lot more bass. Why the freq response looks the same - don't know. You can see that this particular set of measurements was done at 65dB, well below my normal listening level of 80dB. At 65dB, I don't think I could tell the difference between the amps just by listening. It's only 20dB above ambient noise. Why was it done at 65dB? Because the microphone (which belongs to JA, on stereo.net.au forums) is an ex-military mike which is very sensitive to feedback. Any higher and the mike would suffer problems.

And Scorp i'll have sex with you any time, you sexy man

thing with FR's Amfibius is that they dont measure transient response. could it be that the differences heard are related to the transient response? after all, the transient response does have a significant impact on the timber of the music.