[shafu]

I've seen this classification primarily for amps, but some times for CD players as well. Does this mean the quality ranking? Or the power type? Does class B mean better or worse?

Sorry I don't know the basics...

 

[zzz]

these classes talk about modes of operation of the output stage in an amplifier/buffer.

if you don't care about the electronics involved, then it suffices to know that class A is the best and is the only one acceptable for amplifiers/buffers providing low power signals like outputs of CD players or headphone amps. power amps is a different story but good (and heavily heatsinked) designs are still class A or some modified class H amplifiers.

if you do care, google it.

 

[JMT]

This might help:

A Touch of Class: How To Speak "Ampese"

 

[shafu]

thanks for the information guys. Clarified quite a bit for me.

 

[mbriant]

Thanks for that link JMT. Ian Masters worked for me for 13 years as a contributing editor and later as editor. I had lost touch with him. He's as knowledgable as they come about A/V equipment.

 

[lini]

Class A means the amp is using a fairly high idle current in order to achieve the most linear amplification.

Greetings from Munich!

Manfred / lini

 

[da_burl]

I'm sure there are a lot of people who might think it means it was rated Class A by Stereophile!
But I think the best way to think of it is as was stated in the link above, the circuit is biased so that the signal always stays above "zero", or as they put it, more positive/less positive, as opposed to positive/negative. It does usually put devices into their most linear region, and eliminates dreaded crossover distortion.
Funny, I remember my test from tech school years ago where we had to remember Class A, Class B, Class AB, and Class C amplification with transistors. Not that I have used it much since then, until this little headphone thing came along!

 

[lini]

off topic

da_burl: Great avatar!

Greetings from Munich!

Manfred / lini

 

[da_burl]

Lini:

Thanks, that's the 2nd compliment I've gotten today! And I was thinking about changing it!

Guess I'll wait until I post something that reflects my avatar, then change it!

Have a good one

da_burl

 

[shafu]

Yeah da_burl, great picture! Is that you?

Oh, also thanks for answering my question.

 

[ServinginEcuador]

To help remember the specifics of biasing, here's a quick gouge sheet for you:

All classes are a ratio of input to output signal. How much of that ratio is expressed in the following:

Class A - outputs for all 360 degree of the input signal.

Class B - outputs for 180 degrees of the input signal. It cuts off the other 180 degrees.

Class AB - outputs for more than 180 degrees, but less than 360 degrees of the input signal.

Class C - outputs for less than 180 degrees of the input signal.

Class D - high speed digital switching which can imitate another class, mostly class A, but the output is switched off and on like 100,000 times per second or more. More efficient, and is supposed to sound good to. PS Audio's HCA amp uses this scheme quite well.


Hope this helps a little. It's easiest to understand when you have an oscilloscope output showing what is meant, but you get the general idea from this and the web site.

 

[da_burl]

Serving Ecuador:

Yes, that is another way to look at it. Should note that usually Class B Class AB have a complimentary output that produces the other 180 degrees. The old push-pull arrangement Class AB was a modification of Class B, to reduce the crossover distortion again.
Unless you only wanted half the cycle, which you wouldn't for audio!

Excuse me if I'm offbase, I was at Devry in 1981, and as I said, haven't really used it much since then!!

 

[lini]

da_burl: "Unless you only wanted half the cycle, which you wouldn't for audio!"

That would be the all new Audio Lite (tm), then - with only half the calories.

Grinnings from Munich!

Manfred / lini

 

[wallijonn]

http://www.st-andrews.ac.uk/~www_pa/...rt2/page1.html

don't forget to use the arrows at the bottom of the page(s).