Difference between class D and class AB amplifier

C

cptslow

Audioholic Intern
Hi Guys,

Is it true that audiophiles prefer class AB over class D amplifiers ? As i have read class D is more efficient so less heat and less bulky. I see CROWN amplifiers fairly in-expensive and the spec sheet does not look that bad. Is there a difference in the music quality when using a class D amplifier? Any input is appreciated.

--thanks
 
slipperybidness

slipperybidness

Audioholic Warlord
Hi Guys,

Is it true that audiophiles prefer class AB over class D amplifiers ? As i have read class D is more efficient so less heat and less bulky. I see CROWN amplifiers fairly in-expensive and the spec sheet does not look that bad. Is there a difference in the music quality when using a class D amplifier? Any input is appreciated.

--thanks
LOL, what a can of worms.

Yes, "audiophiles" prefer class AB over D, but it is mostly superstition and not based on measurements. But, a "true audiophile" will tell you that pure class A is the key to sonic bliss, not class AB :rolleyes:

Class D amps really have more in common with switching power supplies than they do with the classic class A, B, or AB amps.

There are many advantages to class D, more efficient, don't need the hunking transformers that class A does, so therefore they are lighter (and could be cheaper due to the less expensive transformer).

Historically, the first few generations of class D had problems at high frequencies. For class D to amplify without distortion, the switching of the class D amp must be orders of magnitude faster than the frequency of the highest freq signal to be amplified (i.e. 20kHz for audio).

Modern class D amps are "every bit as good" as class AB (per the measurements), and are better in many regards (efficiency, weight, etc).

Personally, the day that I can build a proper HT, I will probly use the Crown Drivecores, or maybe the similar QSC. For music, I will stick with class A or AB. That is just personal preference, has pretty much nothing to do with performance.

One other item: Many studio monitors use class D amps built in. Would a sound engineer use a class D amp for mixing if it were detrimental to the sound?
http://www.amazon.com/JBL-Professional-LSR305-Studio-Monitor/dp/B00DUKP37C/ref=sr_1_1?ie=UTF8&qid=1412092570&sr=8-1&keywords=jbl+lsr
 
ImcLoud

ImcLoud

Audioholic Ninja
Class A amps can be pretty large, I heard an ams100 powering a set of Focal bookshelfs and it sounded really good, I didn't get a chance to ab it with other amps, but when you consider price per watt {that monster is around $10k and only 100w pc} it would have to sound a lot better than an AB amp for me to justify it.....

 
lsiberian

lsiberian

Audioholic Overlord
Audiophiles like tubes because tubes look cool. I use class D for my current mains.
 
BoredSysAdmin

BoredSysAdmin

Audioholic Overlord
you mean, Audiophools ? ;)

Yes, modern Class D amps are great and no reasons to get A or A/B unless you need a heater for your place :)
 
C

cptslow

Audioholic Intern
Audiophiles like tubes because tubes look cool. I use class D for my current mains.
I thought ppl like tubes because the music feels warm and alive. I did not know it was just for the cool looks of the tubes.:p
 
lsiberian

lsiberian

Audioholic Overlord
I thought ppl like tubes because the music feels warm and alive. I did not know it was just for the cool looks of the tubes.:p
Maybe in bitterly cold Chicago, but here in Texas the last thing we need is another device warming us up. I can see why you want warmth with how cold it is today. It's even cold down here in September.
 
Irvrobinson

Irvrobinson

Audioholic Spartan
Just a suggestion... consider using the search function on this site. I'd conservatively estimate that there are over one thousand posts discussing your question or some variation on it.
 
ImcLoud

ImcLoud

Audioholic Ninja
Just a suggestion... consider using the search function on this site. I'd conservatively estimate that there are over one thousand posts discussing your question or some variation on it.
Irv what fun would that be, if everyone did that there would be under 10 threads on the entire forum, lol :D
Which home theater should I buy?
Class X vs Class X amplifier?
Tube Vs SS?
Bookshelf and sub vs Towers?
Single $2000 sub vs Dual $1000 subs?
CD vs Vinyl vs mp3?
$1500 dac vs $50 dac?
What song to show off my system?
and of course Do cables make a difference?


Seriously though, its this simple if you like class d then buy it, demo the stuff take a listen and buy what fancies your ears... I personally like the look of a big 100lb class a b amp sitting on an amp stand, most class d's don't have triggers, have bright lights and face controls, as well as rack ears and other aesthetic attributes that I would not consider appealing in my music systems... I used to be a huge fan of the crown drive core amps, but then a few guys that were using them for subs as well as one of mine failed, I also heard a few other stories of them failing so I would rather stick with something like an emo a/b , Sure you may get 250 watts vs 430 watts but keep in mind that is not a huge difference
http://www.amazon.com/Crown-XLS1000-Power-Amplifier/dp/B003HZPKSM/ref=sr_1_1?ie=UTF8&qid=1412124317&sr=8-1&keywords=xls+amplifier
http://www.amazon.com/Emotiva-UPA-200-2-Channel-Amplifier/dp/B008O3AJLU/ref=sr_1_1?ie=UTF8&qid=1412124494&sr=8-1&keywords=upa200

Given the option in the above two amps I would choose the emo...
 
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AcuDefTechGuy

AcuDefTechGuy

Audioholic Jedi
I think it's impossible to know every single case or scenario. Anything is possible.

Perhaps in most cases (average speakers, volume & distance) all classes of amps are about equivalent in SQ.

But it's also possible that in a few cases, not all classes of amps and not all amps are equivalent in SQ.

As usual, if the amp sounds good to you in your system, then it is good regardless of class or cost.
 
G

GIEGAR

Full Audioholic
Hi Guys,

Is it true that audiophiles prefer class AB over class D amplifiers ? As i have read class D is more efficient so less heat and less bulky. I see CROWN amplifiers fairly in-expensive and the spec sheet does not look that bad. Is there a difference in the music quality when using a class D amplifier? Any input is appreciated.

--thanks
Only if you can see it, James. ;)

If you're considering the Crown Audio XLS DriveCore Series, it's worth stepping up to the XLS1500, even if you don't need the power hike. The XLS1500 (and above) are slightly different animals with some superior quality internals and consequently are reported to be more reliable than the XLS1000. The differences are only reflected on the spec sheet in the 6dB poorer SNR (>96dB vs >103dB) for the XLS1000 compared to the rest of the line. (Spec sheet: http://www.crownaudio.com/media/wysiwyg/XLS/XLS-DC_datasheet.pdf)

What's your intended application? If you'll be hooking up to an AVR or pre/pro, it's highly recommended to go through a gain structuring procedure to ensure optimal system performance. This is the best and most comprehensive article I've found on the subject: Gain Structure for Home Theater: Getting the Most from Pro Audio Equipment in Your System - Home Theater Forum and Systems - HomeTheaterShack.com.
 
Last edited by a moderator:

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