Speaker Teardown - How do Class-A Amplifiers Work?
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- Опубліковано 7 лют 2023
- We tear apart some second-hand speakers and find out what's inside. And they are based around a class-A amplifier?
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Your channel is a blessing for electrical students like me! Keep it up!
Thanks! Its good to know these videos help people. :)
I was like you some 20 years back. Now, I only watch youtube and get excited from other's project. BTW, the power amplifier to drive speaker is never class-A. It is mostly class-D as that is the cheapest one gives most bang for bucks.
I also shop at thrift stores. You never know when you will find a hidden gem -- at a great price!
Definitely!
Class A amplifier does not mean one transistor. It normally has the same stages as a class B amplifier: input stage, voltage stage, current stage. The difference is that class A and class B is biased differently.
The misunderstanding is probably due to it being possible to make a class a of one transistor, but that is not usually done in real life. I say "usually" just because there exists some amps called Zen. But most class a you buy have just as many transistors as a class b.
Nice
Thanks
Theese kinds of speakers almost always use a class AB chipamps, theese chips are pretty fun to mess around with and build crappy DIY amps because you often need like 5 external components. TDA2822 is an example of what you can usually find inside of a cheap pair PC speakers. TDA 7294 is an example of what you can often find in a sony Trinitron TV. What you got in theese speakers appears to be something in the middle of theese two. That is a pretty beefy looking amp for PC speakers often reserved mostly for higher end pairs meaning that the speakers you got probably weren't all that bad.
AFAIK there is no class A chipamp.
In the class A transistor couldn't the output be where the ground is?
Do you mean switching the ground and outputs?
I mean using no ground
You need the ground to "be the bottom" of the amplifier. The amplifier can only output from between the VCC and GND markers.
Couldn't it work without resistors?
Which resistors are you talking about?
@@SineLab in the class A amplifier. Couldn't you just use one transistor and nothing else as an amplifier?
Well, you would need at least one other component drop voltage along with the transistor. Whether that be a resistor or current source, or something else is up to you.