is the o2 a class A amp? what does class A mean?
Jul 19, 2017 at 10:19 AM Thread Starter Post #1 of 3

Jerrod

Head-Fier
Joined
Jul 11, 2017
Posts
67
Likes
4
Location
MW
I did google it, and i read a bunch of articles, but I still have no idea what class A means - can anybody explain it in simple terms?

Is the o2 a class A amp? is there any noticeable benefit between a class A or any other amp? how many classes are there? A B C D E F G? what's the difference in them?

thanks
 
Jul 19, 2017 at 11:46 AM Post #2 of 3
I did google it, and i read a bunch of articles, but I still have no idea what class A means - can anybody explain it in simple terms?

Think of fictional energy weapons like positron cannons or beam sabers. If you want to be ready for action and totally minimize actions for a reaction, you keep the weapons powered on - positron cannon outside of the re-entry/anti-weapon armour charged and therefore generating heat and also a more spectacular explosion if that weapon takes a hit, or you always have your beam/light saber not just drawn but also the beam activated, which will either drain the main batteries running off the Epyon or Providence (since the beam saber is connected by a cable) or the beam saber's deuterion battery on the Freedom or Justice, or wear out the Kyber crystal, or you accidentally lop off a finger.

A Class A amp's circuit basically operates like that - fully open and drawing full power even with the variations on or even the absence of an input signal, and worse if no transducer is connected.

Another way to think about it is if you have an entire football/rugby team always posing like they're about to start a play, all the time (like, even during a time out), except when actually in play, so when the ball moves they spring into action.

By contrast a Class A/B switches over at some point from A to switching B, kind of like retracting a positron cannon or sheathing a beam/lightsaber. The thing with A/B though is the engineer can set the crossover point differently. Some amps run Class A for a lot more of its output range before switching over to Class B, some switch over early.


Is the o2 a class A amp?

It's A/B.


is there any noticeable benefit between a class A or any other amp? how many classes are there? A B C D E F G? what's the difference in them?

Avoiding crossover distortion and noise on Class A/B. Note that just making a Class A circuit much less tweaking a Class A/B amp's Class A bias will not automatically make a superior circuit since you can actually end up increasing noise, not to mention you get less power output for the same power supply capacity, so you'd have less power before you clip. Although the latter problem isn't as much of a problem with headphone amps since they can easily make a reasonable size Class A amp that outputs enough power to drive practically any headphone to rip eardrums when worn (even before they clip on a lot of headphones) unlike speaker amps where producing just 15watts necessitates gigantic heatsinks but you'll clip driving 86dB sensitivity speakers in most rooms.

Class D has very high levels of distortion and noise, but was used for subwoofers since 10% distortion isn't all that audible if your goal is to pump 500watts into a subwoofer to crack a windshield or shake a house.

Fullrange Class D still has higher THD but a lot less noise than some Class A/B and so became very popular in the past 15years, but still, 0.01% THD vs 0.001% THD isn't all that bad. You have more problems from clipping an 8wpc amp by choosing the wrong speakers.

Other amp classes basically are more efficient but have higher THD+N. That's why you can get a relatively cheap pro amp designed for running stadium speakers but put it in a quiet room and chances are it will have noticeably higher noise than a home use amp. They don't really have to bother with it as long as you can't hear the noise farther out from the speakers, not to mention they don't have to crank it up before there's any signal through it, and standing while dancing or moshing in a large crowd makes it even less likely you'll hear the noise. There are a few exceptions of course which is why some people spend $300 on a dual mono Class H pro amp to use at home (like Crowns, plus some Behringer a few years ago), but of course even at 25watts output even a Pass Labs F5 still has a lot lower THD+N than the Behringer. Use an 85dB/1w at 1meter speaker in a large room though and getting 75watts is more important to some than keeping distortion and noise low.
 
Last edited:

Users who are viewing this thread

Back
Top