Re: Why are "engineers" so poorly educated?

In article <4725d70e@xxxxxxxxxxxxxxxxx>, keithr <keith@xxxxxxxxxxxxxx>
wrote:

To state the bleedin' obvious, a class AB amplifier is not a class A
amplifier. You would bias it rather differently to a pure class A job.
Class AB is a clever hack or kludge to get over the deficiencies of both
class A (dreadful efficiency and excess heat) and class B (crossover
distortion). Class B is the only one that scales to high power, and as the
crossover distortion is a fixed amount, it's significance diminishes as the
power level rises.

It is not obvious that only the class B amplifier "scales to high
power". For example the RCA 50A AM broadcast transmitter used a SE
class A modulator that I estimate was good for an audio power output of
at least 16 kW, not a lot, but not to shabby either, for a class A
amplifier.


Regards,

John Byrns

--
Surf my web pages at, http://fmamradios.com/
.

Relevant Pages

  • Rebuttal to Richard Clarks comments on my Chapter 19A
    ... RF power window at the input of the pi-network, ... plate, and the slope of the load line. ... the amplifier in this condition will later be shown to be 50 ohms. ...
    (rec.radio.amateur.antenna)
  • Re: Rebuttal to Richard Clarks comments on my Chapter 19A
    ... RF power window at the input of the pi-network, resistance RLP at the ... plate, and the slope of the load line. ... the amplifier in this condition will later be shown to be 50 ohms. ...
    (rec.radio.amateur.antenna)
  • Re: why it isnt so important, but still has meaning (long!).
    ... > amp, it may in some cases lead to problems, of which some are outlined ... > Let's assume an amplifier stage with BJTs in class AB such as we find ... > Good, negative loop feedback linearizes the amplifier's properties, so ... > Then we have the physical limitations of the power supply. ...
    (rec.audio.opinion)
  • DF: why it isnt so important, but still has meaning (long!).
    ... we have an ideal voltage ... amp, it may in some cases lead to problems, of which some are outlined ... Let's assume an amplifier stage with BJTs in class AB such as we find ... Then we have the physical limitations of the power supply. ...
    (rec.audio.opinion)
  • Re: Supersizing SET
    ... elliptical loadlines may be accomodated with less distortion than with ... Negative Voltage feedback makes such an amplifier ... Except for the power level. ...
    (rec.audio.tubes)