is D class that much better than a/b?

[jeremiah 10+ year member]

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

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[dragnix 5,000+ posts]

i think at around 500-600watts it won't hurting ur electrical that much with a class a/b. I'm sure it would be fine wit ur electrical, but wait for others to chime in too //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[onearmedbastard 10+ year member]

Class D is a lot more efficient ...
Peak Efficiency:

Class D = 60% - 90%

Class A/B = 35% - 70%

1/3 Output Efficiency:

Class D = 60% - 90%

Class A/B = 20% - 50%

This not only means less power draw, but also less heat produced, smaller chassis size, etc. However, Class D typically has a limitied frequency reproduction and has worse SQ (although it can be hard to tell with bass) ...

x2 was about to say that word for word

 

[n2audio 5,000+ posts]

at 600w your alt should be ok. Class D would be "better", but at that amount of power the efficiency doesn't make as much difference as it would at 1000 or 1200w.

I ran about 1000w rms with a 75A alt for a couple years (700 class D, 300 A/B). No problems to speak of - some minor dimming at high volume.

Here's an affordable full-range class D ~500w bridged at 4 ohms.

http://cgi.ebay.com/Lanzar-OPTI-600-Watt-2-Channel-Digital-Car-Amplifier_W0QQitemZ230142906834QQihZ013QQcategoryZ39732QQtcZphotoQQcmdZViewItem

 

[fwb_1234 10+ year member]

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.

I realize these are posted numbers, but it through me off when I saw those figures.

Another useful figure that eD included was MAX current draw. You might be able to find that for your alt and then make a judgement based on that.

My current system (listed below) has an A/B 2 channel amp powering the subs at a stated 800W. I have some light dimming with my 90A alt., but big3 helped alleviate that problem somewhat.

 

[n2audio 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.

We'll never know for sure - but I'd bet the .4 is optimal eff (full power) and the .1 is ave. Or it's just a misprint.

A/b's run 30-40% at typical listening volume - they don't get close to 60% until they're at max output.

If someone built one that was 60 or better all the time it would be BIG industry news.

Class D's are generally close to, or better than 70% throughout their range.

 

[frzninvt 10+ year member]

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.

 

[Loud3 10+ year member]

We'll never know for sure - but I'd bet the .4 is optimal eff (full power) and the .1 is ave. Or it's just a misprint.
A/b's run 30-40% at typical listening volume - they don't get close to 60% until they're at max output.

If someone built one that was 60 or better all the time it would be BIG industry news.

Class D's are generally close to, or better than 70% throughout their range.

Arc Audio's 3000wrms AB monster.

 

[phantom240 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

 

[luvinthebass 5,000+ posts]

my Kenwood class D amp hit the lows pretty good, wasn't a clean sound really prolly cuz i used bass boost...

 

[Twistid 5,000+ posts]

A/B comes before D , so its that much buch better than d class

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[Loud3 10+ year member]

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

What you're describing does not sound like an issue with a class D vs an AB.

Sounds like the 1200D has a much higher damping factor, which is what sustains the note and draws it out insted of just punching and going off.

There are AB class amps with INSANE damping factors... so, that arguement is null and void.

 

[phantom240 5,000+ posts]

What you're describing does not sound like an issue with a class D vs an AB.
Sounds like the 1200D has a much higher damping factor, which is what sustains the note and draws it out insted of just punching and going off.

There are AB class amps with INSANE damping factors... so, that arguement is null and void.

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.

Switching amplifiers like Class D amplifiers generally have a lower DF than their Class A/B counterparts because the output of the amplifier has to pass through an inductor. Since the inductor is wound with copper wire which has resistance (albeit a very low resistance), the DF is reduced.

Directed '06 model 1200D:

---Type Class D Mono

---Maximum Power 1200 Watts

---CEA S/N Ratio

(referenced at 1 watt/4 ohm) 60dB

---CEA Additional Power

(power into X ohm, all channels driven, 14.4V supply 1% THD+N) 600W x 1 @ 1 ohm

---Frequency Response 20 - 250Hz

---Damping Factor >50

---Crossover Type Variable 12dB low-pass

Alpine MRV-1507, '01 model

---Power Output: RMS Continuous Power (at 14.4V, 20 Hz to 20

kHz)

MRV-1507

Per channel into 4 ohms ......................... 225W, 0.08% THD

Per channel into 2 ohms .......................... 450W, 0.3% THD

Bridged into 4 ohms ................................ 900W, 0.3% THD

Frequency Response ................... 10 Hz to 50 kHz (+0, –1 dB)

---Signal-to-Noise Ratio

(referenced to rated power) ........................................ 105 dBA

---Damping factor

MRV-1507/MRV-757 ................................ Greater than 500

So, Directed 1200--- >50df

and, Alpine 1507--- >500df.

Yes, my amp has an insane df rating.

 

[thylantyr 10+ year member]

Since the inductor is wound with copper wire which has resistance (albeit a very low resistance), the DF is reduced.

The comedy of DF.

Now take your class AB amp and hook up some speaker wire from the

amp to woofer, it's also copper wire which has resistiance, DF is reduced.

lol

 

[phantom240 5,000+ posts]

Yes. But this is a given with any system, A/B or otherwise.