Another concern is nonlinear currents getting induced into circuitry from other very nonlinear current waveforms that flow in each half of the output devices in a class AB design. In a class A amplifier, all current paths, including the high current ones carry only the full waveform of the output signal since there is no reconstruction-from-two-halves going on. So wiring is less critical.
Basically, it is harder to screw up a diy build of a class A amp than a class AB amp, provided you get past the initial hurdle of generating enough DC power and getting rid of all the waste heat.
Basically, it is harder to screw up a diy build of a class A amp than a class AB amp, provided you get past the initial hurdle of generating enough DC power and getting rid of all the waste heat.
Bang-on. It's much more likely to perform like simulation said it would. Lower complexity also tends to help.
As a rule of thumb, the more efficient something is, the more "dirty" it gets and the more engineering work it requires. Switch-mode power supplies are a first-rate example.
Basically it is that simple, it just isn't simple to apply tons of feedback, especially at higher frequencies. Circuitry running at low currents tends to have rather limited bandwidth, and the complexity-performance-power triangle tells you you'll need more of it, which means a lot more poles. That means you'll have to get clever with all kinds of local feedback, nested feedback, higher-order compensation and whatnot.I think, the idea was that if you have a lot of OLG, and then apply a lot of GNFB, it's sort of doesn't matter what class your output stage is - massive GNFB will correct everything.
Well... if it would be that simple
Current-starved output stages also tend to not be very amused when faced with lower-than-planned load impedances. And as mentioned, making a circuit like that work well in practice can be hard for all kinds of reasons. So it shouldn't be a big surprise if amplifiers of this kind aren't super-popular in DIY circles.
Isn't it so that most DIY project are class A simply because it gives a DIY-er most value for money. If you buy a factory built amp for $300 you'll get so much decent sound for the money that a similar priced DIY project will be almost impossible to put together.
Just the cooling fins and the capacitors will cost more. But when it comes to things that approaches high end, things are the other way around.
You may build a very good class A amp for, lets say $1200, that probably will match many high end stuff that costs ten times more.
I don't think it is harder to get a class B amp to work properly, if the PCB is made correctly. But why build a high NFB class B amp, when you have every choice in the world to embrace all of the usual audio hobby-horses such as low NFB, class A, minimalistic design, etc..?
I mean, how funny is it to build a "blameless amplifier"?
Just the cooling fins and the capacitors will cost more. But when it comes to things that approaches high end, things are the other way around.
You may build a very good class A amp for, lets say $1200, that probably will match many high end stuff that costs ten times more.
I don't think it is harder to get a class B amp to work properly, if the PCB is made correctly. But why build a high NFB class B amp, when you have every choice in the world to embrace all of the usual audio hobby-horses such as low NFB, class A, minimalistic design, etc..?
I mean, how funny is it to build a "blameless amplifier"?
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