Whats the difference between MOSFET & Class A, AB

I was wondering what the general difference was in MOSFET amps as compared to Class A or Class AB amps.

For the last few years I have been running a Classe CA 300 amp. A couple weeks ago I had a fuse blow on the Classe and it also burnt out a resistor. Knowing the Classe was going to be in the shop I bought a old CJ Motif MS-100 amp.

Now after a day or two of listening I'm thinking this old Motif betters atleast too my ears the Classe so it got me wondering.

Cheers Gary
Class A and Class AB refer to the type of circuit topology or design of an amp.

MOSFET refers to a particular type of transistor. When we talk about MOSFET amp, we usually refers to the output transistors although MOSFET can be used in other parts of an amp circuit as well. The design of the amp can either be Class A or Class AB or other types.
mosfets rule!
^^^^^ Until tubes came along. lololo
Jaybo pretty bold statement;ever listen to tubes????
A MOSFET is an acronym for an amplification device not the type of circuit. BTW it is metal–oxide–semiconductor field-effect transistor. There are other FETs but I too like the old thermionic tubes.
Read some of Nelson Pass's articles on his website. He's a big fan of MOSFETs running in class A mode and I'm a big fan of his ss designs. Is this some kind of trickle down admiration thing? :-).

FWIW, I'm a tube amp lover, especially single ended ones.
Ok guys just my opinion, there is no a clear winner and neither a general rule but only personal preferences.
If you only want be beguiled, maybe there is no alternative to tube and single ended amplifiers in particular.
Personally I think the best thing to do is to have at least two audio systems in which experiments tubes and solid states (among which mosfets) and enjoy the music in function of your daily mood.
I think that you can get WAY to hung up on circuit topology and device type when implementation of the circuit is most important, once you get past the ss vs tube divide. I've come to believe that there are theoretical advantages that tubes provide that allow most any "good" tube design to perform better w the speakers I have than any ss design, but beyond that I have found that the differences between circuit topology and Class of operation are less significant than I had originally thought. I might be all wet for ss amps, since I have not had much experience w them for the last 5 years or more.
I like the concept of two audio systems,sorta like a wife and a girlfriend.
12-16-10: Markwatkiss
I like the concept of two audio systems,sorta like a wife and a girlfriend.

BINGO !!!!!!!! .............:):):):):
I own both a Classe CA-300 and DR-10. The two amps sound a little different, but I would not say that one is distinctly better than the other to my ears. I wish one amp had the combined positive attributes of both. I just listen to one or the other depending on my mood, as said above. BTW Gary, The CA-300 employs MOSFETs as the driver transistors.