On 3/17/2012 10:13 AM, William Sommerwerck wrote:
Isn't "class A" a way of saying "discrete devices, no ICs"?
See, guys? It Worked! Mr. Sommerwerck is a pretty
knowledgeable fellow and even he got the message that the
marketeers wanted him to get.
No, all it means is that the amplifying device conducts over
the full cycle of the signal waveform. A Class B device
conducts only over half a cycle and requires a counterpart
to conduct over the other half of the cycle in order to
accurately reproduce the input waveform at the output. Class
AB conducts over more than half the cycle but less than the
full cycle. Class C conducts over less than half a cycle and
clips everything.
With the right op amp (and a heat sink), you can "pull up" the output stages
into class A.
See, I knew you were smart. This is true, but not everyone
does that. And as far as I know, all op amps work in Class
AB but the bipolar configuration puts the waveform together
at the output, and the good ones do it with very little
distortion at the crossover point.
--
"Today's production equipment is IT based and cannot be
operated without a passing knowledge of computing, although
it seems that it can be operated without a passing knowledge
of audio." - John Watkinson
http://mikeriversaudio.wordpress.com - useful and
interesting audio stuff