Class A electronics

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Simmons

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What exactly does "Class A" mean.....I mean as apposed to Class D...or any other class. I see a lot of manufacturers use this as a marketing buzzword, but how does that translate into the real world. I can't really find specific info on google about Class A electronics, so any links would be interesting to me as well.

Thanks,
Simmons
 
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The reason why it's a "buzzword" is because Class A kinda seems to have a "sound" to it... A sound I'm not going to even attempt trying to describe (or attempt trying to explain how), but there does seem to be something there; even if ever so slight (though it doesn't seem to be all that slight)... Just so you know...
 
Well, with class B or AB you are getting into the unlinear parts of the amplification, and you gonna get distortion. You can minimize it, but it's not easy.
 
Recording Engineer said:
The reason why it's a "buzzword" is because Class A kinda seems to have a "sound" to it... A sound I'm not going to even attempt trying to describe (or attempt trying to explain how), but there does seem to be something there; even if ever so slight (though it doesn't seem to be all that slight)... Just so you know...

Class "A" amplifiers are basically biased to be always on. They draw current all the time. The advantages are
1. They always operate in the linear range and have the lowest distortion.
2. They are much faster in response to the input signal and have far less "line bounce".

When an amplifier is first turned on, it draws more current than it needs for up to a few microseconds. This "bounce" causes unwanted harmonics (some call this harshness) to the amplified signal.

Disadvantage: Class "A" amps draw alot of power and run hot. But, the sound advantages outweigh the disadvantages.
 
Sorry, I was in a hurry, I forgot to list the other advantages:
The advantages can be summarized for a class "A" amp as:

3. No cross over distortion
4. No switching distortion
5. Lower harmonic distortion in the voltage amplifier
6. Lower harmonic distortion in the current amplifier
7. No signal dependent distortion from the power supply
8. Constant and low output impedance
9. Simpler design
 
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