what's a Class D amp in this sub?

[gcmarshall]

what is a class "D" amplifier as it relates to the following subwoofer? is Class D a proven technology for subs? should i be leary of class D sub amps? pros, cons, etc.; based on the specs, does this appear to be a competitive subwoofer?

thanks.

http://www.sumikoaudio.net/rel/prod_r505.htm

 

[Buckeyefan 1]

Class D amps are used in the majority of subwoofers nowadays. Much more efficient, and run cool. That's what you want for reproducing bass.

 

[j_garcia]

Yep. What Buckeye said. They are very efficient which means they do not generate as much heat as a traditional class AB amp. It's a good thing for subs, and most sub manufacturers are starting to use them.

The REL subs are very well regarded.

 

[BassHead]

Class D amps are used in the majority of subwoofers nowadays. Much more efficient, and run cool. That's what you want for reproducing bass.

And some run warm to the touch even in stand by mode.they do not all run cool sorry do not agree with you.

 

[cam]

Class D amps are very efficient. Here is an example: My Paradigm PW-2200 has a 400 watt rms class D amp. Class D amps are around 90% efficient therefore I'm getting around 360 watts going towards powering the driver and 10% wasted in heat. The previous generation of my PW-2200 had a 250 watt rms class AB. At best they run at about 60% efficiency therefore generating about 150 watts of power going towards the driver and the rest, 40% wasted in heat.

And I agree with Basshead, my sub with a class D amp is constantly warm during standby and when driven hard for an amount of time can get on the very warm side.

 

[MACCA350]

Rated output is just that, whether it a class A/B or D. The rated output is the power the amp can/should deliver at the output terminals. The efficiency difference between an A/B and D class amp means that the A/B design will draw more power from the wall outlet to produce the same output as a D class design.

A 120V15A line can supply 1800W. So assuming these efficiency ratings and given perfectly designed class A/B and D amp:

the A/B at 60% can produce 1080W,
the D at 90% can produce 1620W

This is a very rude generalization of the way these amps produce power and not to be taken as gospel, but just to give an idea of how the efficiency effects the output power in general.

cheers

 

[Wingman9]

Are you all nature huggers ? Who cares about power consumption? It is more important to know a class-D amplifier is a digital amplifier. They exist in all shapes and sizes. Power consumption is lower than a comparable class-a/b amp. But from my point of view thats only important if you have a portable battery powered device. For Home audio it is more important to know a sub with class-d amp might have a digital input. If your amplifier has a digital sub-out you can eliminate losses in the connection cables.

 

[MACCA350]

Not important, the whole point is that a D-class amp will give you more POWER at your speakers simply because there is a limit to the amount of power you can suck from the wall. So the more efficient the amp, the more usable power you can get to drive your speakers, which means LOUDER

cheers

 

[highfihoney]

Are you all nature huggers ? Who cares about power consumption?

haha.

 

[The13thGryphon]

There is another facet of the Class A/B vs Class D debate to consider... a typical Class D plate amp, like those used in many of today's subwoofers, costs 6 to 7 times less than the typical Class A/B plate amplifier.

Hmmm, you don't suppose that has anything to do with it do you? Is it really due to the Class D amp being more efficient, or more reliable (which my techie audio repair friends tell me is not the case), or sounding better (which in my opinion it does not), or could it simply be a matter of economics. Less cost means lower price, means more sales.

 

[MACCA350]

I suppose you beleive LP is a better technology than CD or DVD-A/SACD. D-class amps are relatively new to the consumer, but has plenty of potential, given the efficiency and less heat and need for cooling.

From what I've read the technology is improving and is comparable to class A/B designs. So as this technology evolves we may find them overtake the quality of class A/B designs. I honestly don't beleive that Velodyne and other manufactures would use them in their flagship products if they realy were a s**t quality amp

cheers

 

[MACCA350]

Just found this article: The Truth About Digital (Class D) Amplifiers

Also T-class amps, which is a hybrid using the efficiency of D-class and the fidelity of A/B-class amps

cheers

 

[BassHead]

Class D amps are very efficient. Here is an example: My Paradigm PW-2200 has a 400 watt rms class D amp. Class D amps are around 90% efficient therefore I'm getting around 360 watts going towards powering the driver and 10% wasted in heat. The previous generation of my PW-2200 had a 250 watt rms class AB. At best they run at about 60% efficiency therefore generating about 150 watts of power going towards the driver and the rest, 40% wasted in heat.

And I agree with Basshead, my sub with a class D amp is constantly warm during standby and when driven hard for an amount of time can get on the very warm side.

HI CAM your amp may be warm in stand by but after a good heavy movie will be a touch hotter,but thats ok,Also always leave the amp on in standby so it always stays warm, this will be easier on the amp than switching on and off,The amp will last many years longer than having the cool off and than hot again process,If you are leaving for vacation you can turn it off, I have seen many subs with a/b amps that you could not even place your hand on with out burning your self so there you go.Also on the Pw 2200 or 2100 dont be afraid to run the sub on the very hot side like +6-+8 on your receiver at 80hz or under,it can take tons of abuse and even the driver,Fins even on the driver for cooling ,What more can you ask for.

 

[The13thGryphon]

I suppose you beleive LP is a better technology than CD or DVD-A/SACD. D-class amps are relatively new to the consumer, but has plenty of potential, given the efficiency and less heat and need for cooling.

From what I've read the technology is improving and is comparable to class A/B designs. So as this technology evolves we may find them overtake the quality of class A/B designs. I honestly don't beleive that Velodyne and other manufactures would use them in their flagship products if they realy were a s**t quality amp

cheers

Actually, I don't own a turntable or any LPs. I do own over 700 CDs, and around 300 DVDs, and a handful of SACDs and DVD-As... so I think it fair to say that I'm open to new technology.

All I was trying to say is that there are a variety of reasons why audio manufacturers do things... and not all of them are truly for the owner's/listener's benefit.

At this point in time there are indeed some very good Class D amps that would undoubtedly knock out an inexpensive Class A/AB... and there are a lot of good Class A/AB amps that -- to my ears -- sound better than most of the current Class D amps available.

In a high-end sub a Class D amp is likely to be of decent/good quality, and will therefore probably be a benefit. In an inexpensive sub the Class D amp is likely to have been chosen for its inexpensive nature, and the sound quality and reliability will be secondary or tertiary concerns. There are certainly also a number of manufacturers using Class H, Class T, or BASH amps in their products in an effort to try to get the high-power/low-heat nature of Class D and the generally better reliability and higher quality sound of Class A/AB.

Class D may well be the future of amplification; but I wouldn't base my buying decision on the word of the Chief Engineer for Class D Audio at Philips Digital Systems Labs. Given the fact that Philips Digital Systems Labs is one of the larger Class D amp manufacturers, anything he had to say could be interpreted as being rather self serving. I'd prefer to place my faith on independent testing and verification, and a consensus of the general audio enthusiast public.

 

[MACCA350]

Yes I suppose, as with all things, you get what you pay for.

cheers

 

[rollinrocker]

Gee gryph, so cynical!!