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Class A into Class AB

I’m still a little confused about power amplifiers and integrated amplifiers that are class A & class A/B. Like when they say the first 8 watts are class A then it goes into 400watts class A/B. But the same amplifier can be biased to put out 12watts class A then go into 250watts class A/B. It can be biased again for 18watts class A and 150watts class A/B. etc. Ive read that these amplifiers, ones that can be biased like that...and in general all the "first X amount of watts are class A before going into class A/B"...that those first X amount of class A watts is NOT true class A. If that’s true...what is it then? What’s "kind of" class A mean? What’s the point of a "first X amount of watts are class A" then?

tmac1700

Showing 2 responses by holmz

holmz's avatar
holmz
2,328 posts
 

Mostly it is marketing lingo, for a biased amp.

holmz's avatar
holmz
2,328 posts
 

does that make sense? it must cuz nelson usualluy doesn’t fool around and b-s much, but i am wondering how this works

Well the link made it clear that a biogases amp with be running as Class-A until teh signal level exceeds the bias voltage (or bias voltage - 0.6V).

If one is really distressed with crossover distortion, then they could run Class-A on tweeters, Class-0AB on Mids,. And Class-D on woofers.
Maybe in a 10,30 and 200W range.
Of course they need an active crossover then.

But then there are quality Class-D amp that also have low distortion and do not have crossover distortion.

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