BadMunky87TA

What is the best type of amp for sq, a guy at an audio store told me that class d is better for spl since they are cheaper than the other classes, have more power, more efficent, but more distortion. On the other side class a&b,class a will put out about half as much power as a class d, but it will be cleaner with less distortion. Is this true?

BadMunky87TA

eh

mcss383

class d is used for subs because its usuable freq range is only up to 500Hz or so. Now there is another class called class T. It uses similar technology as class d but has a complete freq response.

As far as class a, class a/b, or class b.....BAH! I believe most all amps now a days are class a/b. There are still people who swear class a is a more 'pure' form of amplification. Any truth to that? Nope.

In todays market just find an amp that has the power you need and the features you want it to have. NO amp produced today has audible distortion (when operated in its linear range).

coalyard

Rubbish. The ability of human hearing is well under rated, especially in the mid range frequencies. Most class A/B amps play up to a certain volume in class A operation, then switch to class B. A class A/B output stage features complimentary pairs of transistors, one a PNP, and one an NPN. One transistor amplifies the positive half of the waveform, and the other the negative. While one transistor is at work, the other is at rest. The problem here is time. As the audio wave form sweeps from positive to negative, there is a certain time lag, while very short, can be detected by careful listening. Couple this with the fact that the 'off' transistor has that time to cool (which is the point of A/B operation in the first place), and you wind up with non-linearity that is sometimes easy to detect, especially in not so well thought out designs. This is usually manifested by harsh sounding treble, a metallic ssshhhh, instead of the full brassy sound of a cymbal crash, and a loss of width and depth (especially) of the soundstage.

Class A output on the other hand is biased to always be on, conducting both positive and negative signals. Why is this better? There is no crossover distortion, for one. Class A output stages are always on, and avoid that minute 'blip' of time needed for one set of transistors to turn off, and the other set on. Since most amplifers feature a calss A driver, or input stage, the circuit is more linear, as discussed above. Finally, Class A output stages are always at the same temperature; they draw the same amount of current whether at idle, or in full swing. If you don't think this is important to sound quality, compare how crappy your system sounds on a cold morning just after you turn it on, compared to how it sounds after it has warmed up.

What are the downsides? Pure class A amps are expensive. They are usually large, don't sport mega-watt power, and they run hotter than hell, which means no stashing them under seats or behind trim panels. Do all class A/B amps suck? Hardly. There are a few designs out there that are great, it is just a matter of what you want out of your system, and how far you are willing to go to get it. I am running 2 Soundstream Reference Class A 3.0 amps to my front speakers, and they totally rock, but I am picky. I am not trying to say that my opinion is the only one, but if amps and audio were that homegenous, we would all own Rockford and be done with it. Use your ears.

mcss383

If you can really tell the difference then you have just won $10,000. Richard Clark has for years been conducting an A/B double blind test between amplifiers. NO ONE has ever won. People that have taken the test are studio production personnel, lifelong musicians, audiophiles, you name it. Amps are set up equally in a scientific mannor.

The human ear isn't very good at detecting differences that are measured with equipment.....

Jim85IROC

iTrader: (2)

Richard Clark's challenge is a complete crock of ****, but more on that in a minute.

A well designed class B amp will have a perfectly smooth transition between the positive and negative portion of the sine wave and will be audibly indistinguishable from a pure class A amp. I've built them in labs with $2 worth of parts and they scoped a perfect sine wave. Any monkey worth his degree should be able to design a good class B amp.

But... since the majority of a/b amps switch over at around 1 watt, 99.44% of your critical listening will be done when the amp is still in class A mode. At 1 watt of output per channel, the average pair of subs in a car environment will provide SPLs over 90dB, which is enough to make it difficult to talk over at a normal speaking volume. 1 watt per channel into higher frequencies is just plain LOUD, and since the human ear is most sensitive to distortion in the midrange frequencies, this is the portion of the amplification that matters the most.

Now... on to Richard Clark. That challenge is a bullsh!t challenge, which is why nobody has been able to collect his $10,000. For it to be "fair" in his eyes, all stages of the "amp" need to be bypassed so that the signal is only passing through the pure amplification stage, effectively bypassing everything within an amp that would have any effect on sound quality anyway. Even a Krako amplifier is bound to provide a clean undistorted output signal as long as it's kept below clipping. It's the cheap-assed junk through the signal chain within the pre-amplification stages (such as crossovers, pre amps, and signal transfer) that ruins sound quality in most amps, so if you're bypassing it, of course it's going to sound ok.

Now... if that wasn't bad enough, RC also eq's the two signals so that their output waveforms look identical. Well... if they look identical, they're obviously going to sound identical.

That's like me challenging a Z06 owner to a race... but both engines have to be in identical chassis, and we're both limited to applying identical amounts of horsepower to the ground.

mcss383

as far as bypassing 'features', there is no BS to that. He didn't make the challenge to compare amp brand A to amp brand B. He made the test to compare between different classes of amplification (originally home/pro audio). You can't compare a classification of an amp if you have a bass-boost or whatever on one amp and not the other. it defeats the whole purpose of the scientific method (all but one variable the same, in this case its how the signal gets amplified).

Now for the Eq'ing I wasn't aware of that nor do i know the details of how/what he is doing.

And yes a Krako (pyramid, boss whatever) WILL SOUND THE SAME in its LINEAR operating range. THATs the point of the challenge. Does he say buy krako instead of Xtant? Hell no! He warns against it, as do I or any sane person. Does he say that the Krako is as good of an amp as Xtant and the likes? Again. hell no. With the Xtant you get a broader linear operating range, more power before clipping, a quality built amp that will last and hold its value, along with customer service and a good warrenty. THATS what you pay for when buying expensive amps (that and bragging rights), not some magical form of amplification.

In everyday useage will the cheap amp sound as good as an expensive amp? NO, and thats not what the amp challenge is meant to show!! People never seem to grasp that concept!! It was to prove self proclaimed 'audiophiles' (you know, the people with $20k speaker cable) that their beloved class a, tube or whatever wasn't some magical form of amplification (which it has done flawlessly).

Jim85IROC

iTrader: (2)

My point is, his challenge is totally bogus. When you remove everything from two devices that could have an effect on sound quality, then the fact that they sound the same is completely pointless. That doesn't help anybody choose an amp. Take 2 black boxes. Put a signal in, get a signal out. Now compare. I don't know about you, but I don't disassemble my amps, make my own pre-amp, bypass the signal path through the box, and then repackage it. I buy it and hook up my RCA and speaker cables. That's how the tests should be conducted in order to provide any sort of useful comparison between 2 products. Proving that Product A and Product B have the same amplification properties is as useful as comparing the octane of the gas in a Z06 and a geo and proclaiming them equal cars.

mcss383

*sigh*

You almost have the concept of it, but you just aren't grasping WHY he did it and for what reasons!

I'll repeat it again:

"In everyday useage will the cheap amp sound as good as an expensive amp? NO, and thats not what the amp challenge is meant to show!! People never seem to grasp that concept!! It was to prove self proclaimed 'audiophiles' (you know, the people with $20k speaker cable) that their beloved class a, tube or whatever wasn't some magical form of amplification (which it has done flawlessly)."


No where ever in his challenge is it said to use it to choose an amp. Thats completly beside the point of the challenge!!!!!!!! The only point of it is, Class A, Class B, Class A/B etc etc sound the same. When you do an A/B test of just those variables you cannot pick out which is which! That is why you HAVE TO ELIMINATE ALL OTHER VARIABLES. Do you understand the concept of the scientific method? I know your are a very intelligent person, which is why I'm dumbfounded that you don't see this.... It has nothing to do with whether or not a Sound Stream, Xtant, McIntosh, Zapco etc etc will perform as well in everyday use as a Krako, Boss, Pyramid etc etc.

CAMp3RO

but the reason why jim and others find the test pointless (including myself) is that it eliminates all of the "goodies" that make one amp better than the other. a person does not buy a pure amp. the stuff such as crossovers, filters, etc is part of the reasons why people buy certain amps over others. dealing with the class thing now. if your ears arent golden, and 99.95% of the public's arent, you dont need to spend the money for a class a. uses mucho power, puts out not many watts. you wont know the difference between a class a and a class a/b. class d is great for subs. the distortion levels on the newer ones are minimul to none, so you get lots of power for little money. best example, the rave of many sound guys, is the JBL 1200.1. puts out over 1200 watts and can be found for around $300. unheard of but a few years ago. i'm going with two class a/b (ample audio a240x and a218x) because ample's class d's were too powerful for my single amp. i chose my amps on specs, quality, and price. much like everyone else should do.

oh, and i agree on the audiophile idea. if you dont have noise in your system, you wont benefit at all from better interconnects. the only difference you may notice is when you have too small of wire going to your subs. at times, i think audiophile is just another name for a rich snob who has too much money to blow and not enough stuff to buy

mcss383

I fully understand and agree with that Camp3ro, but it still has nothing to do with the amp challenge. You should choose amps based on build quality, x-over quality, other features you like because the classification of the amp does not affect sound quality (to an AUDIBLE extent) so therefore its not an issue to worry about!! Thats the point i was trying to make and its the same reason as to why the amp challenge is set up the way it is! It proves class a, class b and such sound the same so therefor buy an amp you can afford, like the looks, acceptable efficiency, x-overs blah blah blah.

Now if you just WANT a class a amp to say 'hey i have a class a amp', more power to you. Car audio is about personnal enjoyment, if you just enjoy having that class a amp, by all means, enjoy!

Also, isn't the webster's definition of an 'audiophile' a rich snob? hehe

Jim85IROC

iTrader: (2)

I know what the amp challenge is, and that's why I realize how totally pointless it is. Our discussion is walking in circles here chief. I know his challenge is to prove that one amp sounds exactly the same as the rest. But to me, that's totally obvious, and also totally pointless. It's a worthless challenge to answer a question that nobody with any intelligence is asking anyway.

I'll give you $10,000 if you can stare into the sun for 10 days non stop and still have your sight. Does it prove a point? Yeah. Does anybody with a friggin brain already know the obvious answer? Yeah.

Maybe non-electrical engineers don't realize how blatantly stupid his challenge is, but to me it's pretty obvious. Considering your pretty thorough circuit knowledge, I'm real surprised that you don't feel the same way. I've built and tested enough amps to know that within their linear range, their output is very, very clean no matter what type of amp it is.

I agree that buying an amp based on its classification is dumb (except class D, but that's a totally different story), but when shopping for amps, it's really important to make sure you know what you're getting, because with most amps, what comes out isn't the same sine wave with a higher amplitude.

mcss383

the reason I don't feel its pointless is because 90% of the people have no freakin clue about.....anything. lol You then have multi-million $$ marketing schemes with the addition of aforementioned rich snobs (lol) that totally cunfuse the public and make them believe there really is an audible difference and they sell their JL, Kicker, RF, MTX or whatever for a Sounstream, xtant and such to find out.....it sounds the same (although unfortunatly many people fall victim to the placebo effect) and they are out a ton of money....same goes for capacitors, additional batteries and such.


Oh well, mature debate is always fun Its been a while so I guess I was just lookin for one! hehe



PS: I got to get my post count up some way or another. lol
:lala:

coalyard

Sorry guys, I do work nights, so I got to miss the prime time debate on this subject. Lots of good points made here, but to clarify my position—Yes, I am an audiophile. No, I do not make tons of cash, nor am I a snob by any means. Especially, I didn't make my choice of amplifiers based on their operation characteristics or their rated specs. I chose Soundstream because of reliability, build quality, and features, not in any particular order. One criterion I didn't compromise on was sound. I was fortunate enough to have connections and be able to test different brands of amps in my own system for a period of time before I made a purchase decision. I picked the amps that sounded the best to me, without regard to anything else.

Both mcss and Jim make good points in saying that there is often too much weight put on specs, advertising and image, especially when marketing products to those looking for maximum boom for the buck, and an unlimited credit line. Who can blame them, as long as they provide an acceptable product.

My point is, are there differences in SQ between amplifiers? Certainly. Otherwise, we would all own Kraco or Optimus amps, and be done with it. The reasons for those differences are due to a number of factors, including those pointed out above, and those in my previous post. Match a top notch amp and speakers with a Kraco head unit and what will you get? Loud, ****ty sound. I think a more interesting discussion could be had on proper system design, since that is an often overlooked subject by those looking to rush into the realm of high end car audio, often pushed by salesmen who don't have the foggiest idea about what good sound is, let alone how to achieve it.

What say, Jim? Mcss383?
T

Jim85IROC

iTrader: (2)

It's nice to argue with somebody that actually has the ability to back up what he says, instead of just spouting off BS that he can't support.

Anyway... I still DO feel that there is a SQ difference between say an Xtant and an RF (or similar) amp, although too minor for me to pay the extra money for. But... it's not the amplification stage that causes the difference in SQ. This is where RC's challenge fails. I don't give a **** what components underneath the heat sink are causing the differences in sound... as a listener I'm only concerned that those differences do in fact exist. Sure, the a/b vs. pure a propaganda isn't the reason... it's the other gizmos under the heat sink, but the fact is, differences do exist, and RC's challenge completely eliminates those from his test. So what do we wind up learning? Do we learn that there's an audible difference between a Kicker and an RF? No. We learn that there's no difference between the two when all except the aplification stage is eliminated. That doesn't help me find the better sounding unit tho.

The reason I bitch about this so much is because when I worked at a place that sold home audio equipment, I used to be able to tell what receiver was playing just from the sound of the music. (I could only do this with 1 or 2 songs that I auditioned hundreds of times). I could walk in during somebody elses demo and if they were switching back and forth between an Onkyo and something else, I could pick the Onkyo out every time. The onkyo had a very unique sound that I could pick out every time. Customers thought I was crazy, but anyway. But.. if you bypass all of the processors and EQ the two signals, then I'm sure that onkyo will sound the same as all the rest, but that doesn't help me when I'm shopping for a receiver.

mcss383

Jim:

well sure, I totally agree. I was just pointing out, that wasn't the point of the amp challenge (all the other gizmo's).

Yep, and the challenge wasn't meant to be a testing ground for finding thus said better sounding unit.....although there are plenty of 'Clarkies' that spout off the challenge as if thats what it is proving.

I hear ya there, I hate the sound our Sony 935 reciever makes when the EQ is used....its the crappiest 'EQ' (i wouldn't call it an eq, but they do) I've ever seen.

--------------------

coalyard

I hope you didn't take my statement personal, because it was in no way referring to you, although you had me wondering there for a little bit .

I agree as long as 'amplifiers' is meaning the whole package , although going back and reading my second post that wasn't very clear...sorry.

Yeah that would be a good discussion, it would help save newcomers from wasting tons of money (like i have ), but thats outside the realm of this threads topic. Maybe another time.

BadMunky87TA

ok, i kinda understand what you guys are talking about how every thing will sound the same at just the amplification stage
but after throwing all the factors in is there any class that has a clear advantage?

why i am asking this is right now i have two audio shop competing for my money
my setup as of right now 2 kicker comp VRs, brigded to RF 360a2
alpine 6x9s, RF 4x6, alpine 4ch Vpower amp (used for a week by a friend and bought it for $100) and pioneer hu, i like my system decently but i want more accurate bass and louder bass too.
one shop wants to do gradual, starting with a new amp, memphis class d amp,rated 1000w and maybe new subs if i want more boom (IDQs)otherwise new plates,or kicks!!

the other wants to do a Pheonix gold class a&b amp rated at 300w? and pheonix gold tantrum series subs. The guy here said they would pound hard because something would pull the sub back down after it went up and they would have better SQ because of the build in filters. Also what do poeple mean when they say "it will give you a CLEAN 100ws"?

CAMp3RO

the whole clean dirty thing is a misnomer (sp?). 100 watts is 100 watts. part of the whole difference in amps is at what point do they start to distort, or you could say dirty. for subs, its kinda pointless to spend the money on an a/b amp as opposed to a class d because there is little difference if any in the sound. the idea of pulling the sub back?? wtf? if you change the motion/speed/etc of a sub, you change the pitch, so thats BS. go with a good class d, the memphis is a good one or also the jbl's, and a couple of good subs.

mcss383

i think the pull-back he was referring to was probably the damping factor of the amp. Yeah, thats another one of those 'inaudible things' with todays amps. As long as an amp has a factor of 50 or better its fine (which all do today that I am aware of). Any more just gives you bragging rights.

As far as the shops recommendations, I would def go with class d for sub. Why tax your electrical system for no reason? The first option you listed sounds good to me. Memphis amps are very good and IDQ subs are also a good sub. On option 2 change over to a class d amp for the sub and it too would be a good option. Find something you WANT. looks, features, etc etc. Make sure you demo each product, most have a distinct sound.


From what I've gathered, when people say this amp has CLEAN 100w they are either trying to sell you something, or just dont have a very good understanding of electronics, or use that to imply it actually produces 100w and not a Pyramid 'claimed' 100w. In the case of a salesperson its a good chance its the first two. lol Otherwise its just like Camp said, 100w is a 100w.

NEEDforSPEED

i can with very powerful welding glass's
can i have my $10,000 now??
hehe!!:lala: