Noob Stereo Question

[perry386]

Ok, so the I was listening to the stereo I have in my room the other day and I noticed the receiver said class H+ on it, and then I was reading a stereo post on here and Earmark said something about class H and D and I was just wondering what are the different classes of stereo systems and which is the best in therms of power and audio quality. I know this is probably remedial to you guys but I'm semi-new to this so help would be appreciated.

[EarmarkMarine]

Perry,
There is Class B that applies to a portable radio or Class A that applies to esoteric home gear. In an auto or boat, you are likely to see Class AB, Class H and Class D.
When it comes to sound quality, understand that there are good and bad examples in every topology.
Class AB has been the stereo standard since the second half of last century. On average Class AB is 50 percent efficient. So for every 100 watts of supply only 50 watts is delivered to the speakers. The other 50 percent is converted to heat which must be dissipated.
Much like an incandescent light bulb that delivers light but creates a lot of wasted heat in doing so.
Class H is about 40 percent more efficient than Class AB.
Class D is about 60 percent more efficient than Class AB.

David