Class AB vs D

[Haunz 10+ year member]

there you go; the voice of reason. Some class d's don't sound as good as some class AB's. Some do. What a shock.

You can choose any two amps you want.. if they are playing the same bandwidth, set at the same output level, neither is driven into distortion, and there is no sound processing like bassboost used... then you will not be able to hear any difference between them... and it's been proven time and time again in scientific ABX compairsions...

The amount of stupid on this forum almost blows my mind... //content.invisioncic.com/y282845/emoticons/reposthorse.gif.368c1dbb9d02cacf5006b3ed421cde0e.gif

 

[FoxPro5 5,000+ posts]

PDX amplifiers deliver outstanding sound quality. The revolutionary design of the PDX incorporates improved feedback circuitry and power supply filtering system, plus a damping factor that is 350% better than Class A/B amps.

Jesus Christ, are you an Alpine employee?!?! //content.invisioncic.com/y282845/emoticons/rolleyes.gif.c1fef805e9d1464d377451cd5bc18bfb.gif I feel ill.

Alpine PDX amps are small and that's about the only redeeming QUALITY about them.

 

[FoxPro5 5,000+ posts]

You can choose any two amps you want.. if they are playing the same bandwidth, set at the same output level, neither is driven into distortion, and there is no sound processing like bassboost used... then you will not be able to hear any difference between them... and it's been proven time and time again in scientific ABX compairsions...

The amount of stupid on this forum almost blows my mind... //content.invisioncic.com/y282845/emoticons/reposthorse.gif.368c1dbb9d02cacf5006b3ed421cde0e.gif

My explanation sounds better than yours. I just read it, with my own eyes. My eyes don't lie. //content.invisioncic.com/y282845/emoticons/crazy.gif.c13912c32de98515d3142759a824dae7.gif

 

[FoxPro5 5,000+ posts]

I believe there's a difference in sound from class a/b and class d. If anyone wants to switch my PPI PC4100 with their class d amp and do a sound check on my frontstage, I'd like to verify this w/ someone else's ears.

You can compare amps all you want; brand to brand, model to model, whatever. Every amp should sound different to a degree, because not every amp is exactly alike in output, distortion, etc. If you start making an arguement for the **** design of the thing, make a well-founded and intelligent statement....not "cuz me ears tell me."

 

[headless 10+ year member]

Limited to noise, power, distortion, frequency response, and gain...yes they do, every single time, every single amp.
Many many more things to concern yourself about than the supposed "sound" of amp topology. For example, whether the RCA plugs are red and black or red and white. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

Which is approximately like saying a ferrari drives exactly the same speed as a corolla...as long as you are driving 50mph. Which is true, but rather misleading. While modern (and well built) class D amps likely will be indistinguishable in distortion to current class A/B amps across the hearable frequency range, that is because a ****ton of filtering and modulation circuits have been developed in recent years to make it a possibility. Take eclipse's XA line for an example of a class D that can actually perform across wide frequency ranges without distortion...or as was mentioned the PDX line of amps. However, if you pull out an older class D amp without those benefits, you aren't going to see the same output and are going to need to low pass the amp to get rid of high frequency noise in the signal. Not to mention the notorious tendency to introduce nasty distortion around crossover points. Sure, a well built, properly filtered class D will cut all this stuff out. But not all class D amps out there ARE well built nor do they all sound the same.

I do agree that there are many better things to worry about than your amp topology in most cases.

 

[FoxPro5 5,000+ posts]

While modern (and well built) class D amps likely will be indistinguishable in distortion to current class A/B amps across the hearable frequency range, that is because a ****ton of filtering and modulation circuits have been developed in recent years to make it a possibility.

I assume you'll be testing this on a radiating driver that's at best 2% efficient and has harmonic distortion well above that of the amplifier? Not to mention, being filtered itself.

If you get that warm fuzz feeling by putting Class A/B on your fronts and D on your subs, then keep it up and ignore everything you've read. It doesn't matter. If you honestly think your ears are good enough to tell what amp topology SHOULD sound like, then you need get a job at the CIA because you'd be one hell of a spy or something.

 

[Beerdrnkr 5,000+ posts]

You can compare amps all you want; brand to brand, model to model, whatever. Every amp should sound different to a degree, because not every amp is exactly alike in output, distortion, etc. If you start making an arguement for the **** design of the thing, make a well-founded and intelligent statement....not "cuz me ears tell me."

If it's my system and I like the sound of class a/b over class d, than it's all the proof I need!

 

[headless 10+ year member]

lol, you're kind of a dick, foxpro //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif I suppose you don't believe that gold RCA's sound better too, right? //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[Beerdrnkr 5,000+ posts]

FoxPro, what amps do you have?

 

[FoxPro5 5,000+ posts]

If it's my system and I like the sound of class a/b over class d, than it's all the proof I need!

You're 100% correct. No one is denying that. What we're saying is that you're not actually hearing the quality of the design (Class), you're hearing a difference in SPL, noise, gain, power, etc. To say you like A/B over D, in this sense, is asinine.

Thank God we had a guy like RC on OUR side back when he put up his $10k. He was making the same arguement against the manufacturers who tried to sell us "sound quality" bullshit. The same debacle goes on with home audio and the nutcases get even nuttier. It's hilarious to read about, actually.

 

[joetama 5,000+ posts]

Oh man here we go...

I can sum this up in 3 points:

1. Some amps might have a different sound, it might be marginal but it is there.

2. Not all audible parameters can be measured.

3a. Most people either can't hear the difference

3b. or don't have a good enough system to hear the difference.

Most people are going to fall into 3b. Get the Class D to save on power input requirements. A/B is going to get rather hot as well, especially assuming 1500 Watts output is going to be biased pretty harshly to remove most crossover distortion.

 

[FoxPro5 5,000+ posts]

lol, you're kind of a dick, foxpro //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif I suppose you don't believe that gold RCA's sound better too, right? //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

Platinum is the best. You should see the sound quality electrons move through it. They look so happy. //content.invisioncic.com/y282845/emoticons/rolleyes.gif.c1fef805e9d1464d377451cd5bc18bfb.gif

I have an Alpine PDX amp in my car and have used at least 5 different Class D amps on my front speakers (gasp, tweeters!!?!?). You name the amp...all the B&O ICE amps available from the big box manufacturers. Heard them all. I'm not silly enough to proclaim superiority of Class. It just doesn't work that way. And you don't need to use 400 amps to understand how stupid it is, even though I probably have.....//content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif//content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[oldschool4me 10+ year member]

im still a firm believer that the internal components make the amp. you get what you pay for just like anything else. a cheap class d amp isnt going to sound like a high end one, as the same for a/b. cheap amp = cheap sound period. i still love old school amps because of the quality of components. you can still get good amps dont get me wrong but the most of the newer stuff is not near the same quality as old. even new vs old amps of the same company. all people see now is numbers and its sad. its not the numbers they say the amp puts out but what the amp actually does and how it sounds doing it is key. i dont care what numbers they put on an amp and what they tell me it supposed to put out. how does it sound is the question.

 

[FoxPro5 5,000+ posts]

1. Some amps might have a different sound, it might be marginal but it is there.

Who said they all sound the same?

2. Not all audible parameters can be measured.

Which ones cannot? Sound quality is not subjective, sorry.

Most people either can't hear the difference 3b. or don't have a good enough system to hear the difference.

You cannot hear an amp, you can only hear a speaker. Listen to any speaker you want (headphones excluded) and move your head by 2" and it will sound different, even though it may have not objectively/physically changed. Ears are necessary to perceive sound. Sound itself doesn't exist in a world without ears...waves are waves.

Most people are going to fall into 3b. Get the Class D to save on power input requirements.

Totally agree.

 

[FoxPro5 5,000+ posts]

a cheap class d amp isnt going to sound like a high end one, as the same for a/b. cheap amp = cheap sound period.

Confounded to the 5 variables already mentioned, yes it will. It will sound no different. If you actually believe it will, tell me what I need to do get the "cheap" one to sound "high end" other than replace the way it amplifies the signal.