is D class that much better than a/b?

[squeak9798 5,000+ posts]

This isn't always necessarily true.
If you go to eD's webite http://www.edesignaudio.com/edv2/index.php?cPath=22 and then click on the Nine.4 (A/B) and the Nine.1 (D) product specs., you will find that the posted specs for them are 68%, and 64%, respectively.

Without any information as to the conditions under which those numbers were derived, they are pretty useless.

 

[squeak9798 5,000+ posts]

Class D while efficient has a different sonic signature (tone) and is probably best suited for subwoofer duty only. It certainly does not sound as good as a good quality Class A/B amp IMO - YMMV.

Myth.

 

[squeak9798 5,000+ posts]

Class D amps sound MUCH different than A/B amps, especially high quality ones. There's a night and day difference between my buddy's directed 1200D and my Alpine MRV-1507. His subs are sealed, and with my amp, it was tight, punchy, and authoritative. With his amp, it sounded almost like a ported box, with a bit of delay, and hit the lows a bit better than mine did (but he had bass boost on).
A/B amps are known for sq

D amps are known for efficient power

Likely due to the setup of the amplifiers and not a result of the amplifiers themselves.

Just because you remove amp A and install amp B, it does not make it a valid comparison.

 

[squeak9798 5,000+ posts]

No, you have it backwards. Higher damping factor is good, lower is bad.. hence why class D amps arent used as full range amps, but subwoofer duty only where complete accuracy is not an issue.

Entirely false.

There is a wide multitude of class D full range amplifiers in both car and home audio. Almost all of which can be audibly indistinguishable from their class A/B counterparts.

So, Directed 1200--- >50df

and, Alpine 1507--- >500df.

Yes, my amp has an insane df rating.

Damping factor is generally meaningless in anything solid state. They will have adequate enough damping to not cause any audible differences.

 

[squeak9798 5,000+ posts]

OK so I have a mj-18 SVC4ohm I know that a 2chanal amp (class a/b ) is a lot cheaper than a 1chanal (D class ) amp but wont the class a/b amp be a LOT harder on the electrical than the D class amp right? if so by how much?..I would like a 500/600Wrms amp but I have a 75amp alternator will a 500/600Wrms class a/b amp be OK on my electrical?........

think-you

As was pointed out earlier; Most class A/B amps will be operating at very low efficiency with musical content as they are typically in the 30% range @ 1/3 power wereas class D's are typically 60% or better throughout their entire range of power.

So, lets take a few examples pulling #'s out of the air.

We'll say both are 600w amps.

1/3 power of a 600w amp is 200w.

Assuming the class A/B is 33% efficient here, with a 12V power source it's current draw would be 50A

The class D, using a figure of 70% efficiency, with the same power source it's current draw would be 23A.

So @ 1/3 power in this hypothetical example the difference in current draw would be 27A

At full power class A/B's typically increase to the 50-70% range while a class D typically stays around the 60%+ range.

So at full power, with 55% efficiency (using figures on the low side intentionally) the class A/B would draw 91A.

The class D with an efficiency of 65% @ full power would draw 77A

Difference here of 14A @ full power (barely ever realized with musical content)

So there is a hypothetical scenario to give you an idea of what the differences in actual current draw would be. Again, since it was based off of assumptions in reality the differences could be slightly more or slightly less, but it should give you a general idea.

 

[phantom240 5,000+ posts]

Entirely false.
There is a wide multitude of class D full range amplifiers in both car and home audio. Almost all of which can be audibly indistinguishable from their class A/B counterparts.

Really? Hmm... never seen one. I guess you learn something new every day!

So let me ask you, squeak, why is it that nearly every class D amp on the market is for subwoofer use only? This really intrigues me why everyone seems to think that class D amps cant be used full range (as I thought).

So, if we both turned any equalizers (parametric on my amp, +8dB @ 45 hz on his), and set the gains so that they produced the same amount of power at said volume level, and replaced amp A with amp B, they would sound the same? Because we definately didn't get the same audible results.

Also, where the hell do you get all this knowledge from! //content.invisioncic.com/y282845/emoticons/graduate.gif.d982460be9f153bb54e5d4cb744f6ae8.gif

One last thing, squeak, wtf is Slew Factor? I never knew what that was for.

 

[squeak9798 5,000+ posts]

Really? Hmm... never seen one. I guess you learn something new every day!
So let me ask you, squeak, why is it that nearly every class D amp on the market is for subwoofer use only? This really intrigues me why everyone seems to think that class D amps cant be used full range (as I thought).

Couple reasons. One, many consumers have the same view as you (class D = yucky), so from a marketing point of view it could potentially cause customers to not like the amplifier. Secondly, the efficiency gains aren't as significant with smaller front-stage amplifiers as they are with larger monoblocks (the difference in current draw for a 100w amplifier is less than 10A). 3rd is that for a long time they were much more difficult to get to run good full range....but within the past 10-15yrs the technology has improved and they have started to pop onto the scene more.

They are much more prevelant in home audio than car audio at the moment (which seems backwards, given car audio's demand for lower current draw & smaller chassis size)....but Xtant, Alpine, Altomobile and Eclipse have full range class D amplifiers as does Lanzar. There are more, but they aren't coming to me at the moment.

 

[phantom240 5,000+ posts]

Couple reasons. One, many consumers have the same view as you (class D = yucky), so from a marketing point of view it could potentially cause customers to not like the amplifier. Secondly, the efficiency gains aren't as significant with smaller front-stage amplifiers as they are with larger monoblocks (the difference in current draw for a 100w amplifier is less than 10A). 3rd is that for a long time they were much more difficult to get to run good full range....but within the past 10-15yrs the technology has improved and they have started to pop onto the scene more.
They are much more prevelant in home audio than car audio at the moment (which seems backwards, given car audio's demand for lower current draw & smaller chassis size)....but Xtant, Alpine, Altomobile and Eclipse have full range class D amplifiers as does Lanzar. There are more, but they aren't coming to me at the moment.

WUUUT?!?

Hmm... If alpine made a class D full range amp, I thought I would have known. I want it!

I've only heard a couple class D's, but the ones I heard weren't really what I would call "detailed". Of course, I'll give them the benefit of the doubt and say they were crappy to begin with.

 

[squeak9798 5,000+ posts]

One last thing, squeak, wtf is Slew Factor? I never knew what that was for.

Slew rate is the maximum "rate of change" the amplifier is capable of. Essentially if the slew rate isn't high enough, the amplifier will not be able to properly reproduce the higher end of the frequency spectrum. Similar to damping factor, if the slew rate is adequate for the power and frequency range, then there is no benefit to having a higher than necessary slew rate. The amplifier won't "sound better" because it has an excessively high slew rate. If the slew rate is adequate; that's all that is necessary.

Here is a thread that shows what slew rate is necessary for reproduction out to 20khz;

http://www.elitecaraudio.com/forums/showthread.php?threadid=125904

Hmm... If alpine made a class D full range amp, I thought I would have known. I want it!

Alpine's PDX series are all class D.

 

[phantom240 5,000+ posts]

No kidding?

Wow, no wonder theyre expensive.

 

[dipitydoo 10+ year member]

Agreed, with the above statements. Class D amps, while they may typically measure worse than class A/B amps on paper, have indistinguishable sound vs. class A/B amps in the real world. Of course, this is potentially opening up a can of worms. Class D amp's limitations for full range comes from the high frequency switching noise in the power supply. However, there have been several manufacturers that have overcome this limitation and designed full range class D amps. Alpine's ICE amps are one of them, I think Eclipse also uses the same chip, and Tripath's 'class T' chips also allow for full range. As a matter of fact, Infinity's Beta amps from many years back was one of the first class D amps made, and they designed these for full range. You won't really benefit as much from class D amps for your mids and highs versus using them for subs. Mainly, the mid/highs won't require as much power. The biggest advantage I see is the small footprint they might offer if you're tight on space.

 

[Rich B 5,000+ posts]

Class D amps, while they may typically measure worse than class A/B amps on paper, have indistinguishable sound vs. class A/B amps in the real world.

Thats not the conclusion the (home) audiophile magazine The Absolute Sound came to after they tested 8 digital home audio amps in the November 2006 issue.

Editors Roundtable: Editors' First Impressions

What’s the consensus of TAS’s senior editors about whether Class D amplifiers are ready for the high end? To answer that, we recorded a conference call with Jonathan, Wayne, Neil, Chris, and me in which we sum up our listening impressions and views.

Robert Harley

http://www.avguide.com/features/class-d/first-impressions.php

 

[squeak9798 5,000+ posts]

Thats not the conclusion the (home) audiophile magazine The Absolute Sound came to after they tested 8 digital home audio amps in the November 2006 issue.

Editors Roundtable: Editors' First Impressions

What’s the consensus of TAS’s senior editors about whether Class D amplifiers are ready for the high end? To answer that, we recorded a conference call with Jonathan, Wayne, Neil, Chris, and me in which we sum up our listening impressions and views.

Robert Harley

http://www.avguide.com/features/class-d/first-impressions.php

Anything published or stated as being from an "audiophile" source is automatically discounted and generally unreliable. Why? They are the #1 biggest believers in myths, magic pixie dust, fairy tales and all around utter nonsense. The "audiophiles" will tell you marking your CD with a green marker will enhance it's dynamics and tonality. The "audiophiles" will spend hundreds on tiny discs to place around room because it opens up the soundstage. The "audiophiles" will tell you how swapping out the receptacle in the house presented a more precise vocal image or changed the timbre of their loudspeakers.

Secondly; All I see is a bunch of people sitting around giving pure subjective and unverifiable opinion. They have nothing in that article, that I saw, to validate a single one of their statements. Likewise, they do not describe their testing conditions. First and foremost if they knew which amplifiers they were listening to in any of the sessions then their preconceived ideas of class D amplifiers will skew what they perceive.

For a more realistic and scientifically verifiable study on the sonic effects of amplifier topology, I'd suggest starting here;

http://www.talkaudio.co.uk/vbb/showthread.php?s=&threadid=18815

 

[dipitydoo 10+ year member]

Rich B, I like you avatar....had one of those, way back in the days...

 

[jeremiah 10+ year member]

my bad I forgot that I made this thread but WOW! I think that I'll just get a D class amp one day