Class D Amplifier Disadvantages
Today’s topic is very interesting and simple. I will be discussing details about Class D Amplifier and especially the major disadvantages of this class. I have received this question last week and it was asked by Jonathan, who is a regular reader at Stereoauthority.com. Let me rephrase his question, “Can you explain, What is a class d amplifier” and “Class D Amplifier Disadvantages”.
Now, we are moving towards the energy efficient world and with every passing day, technology is getting more focused on class d amplifiers. The problem is that why are not class d amplifiers more acceptable. This is a great question and I will answer this in detail here.
Class D Amplifier Disadvantages
Now before I talk about the class d amplifiers disadvantages, which in the present world is a difficult thing to do. These class d amplifiers have evolved a lot and now with the latest technology and designs, it is hard not to buy a class d amplifier.
Class D Amplifiers are the future of amplifiers. These are among the best versions of amplifiers that are present in the market nowadays. For me, there is no major disadvantage of Class D Amplifiers. These not only deliver high-quality sound but they are energy efficient at the same time.
No doubt the designs of the past were more focused on class A, massive transformers and lots of capacitors and instantaneous amps. Sometimes exceeding 100. But in energy efficient world and we are moving towards class d amplifiers. Class D which does not seems to be obsessed with one on loads and high average and yet class d is not being accepted.
Why is that the internet is filled with articles and posts that are just slamming class d amplifiers. People call it unmusical.
Now let me explain my point of view. I have loads and loads of thoughts on this very topic. The journey for class d amplifiers started in 1958 and today they are most talked about amplifiers. so, it is better not to talk about the class d amplifier disadvantages, rather, I will explain how class d amplifier works. It will up to you to decide if you can find disadvantages in class d amplifiers.
What is a Class D Amplifier?
Class D is analog, even though people consider it digital. In fact, class d is something called post rhythm modulation and it basically works in a very efficient manner like this. An input signal comes in and it is compared to a rising amp. Now you must be thinking what is a rising amp?
Picture of voltage that has nothing to do with the input signal. I call it a triangle wave and you just picture a triangle and that triangle is actually voltage rising from the bass of the triangle to the very peak of the triangle on a very linear ramp and then back down again. So just picture that.
Now we have this, a graph like a letter V, that is upside down in the graph. This triangle wave is going up down, up down and the process continues. We have a device called a comparator and the comparator on one of its inputs, it compares two things. So in one input, the rising triangle wave is compared to the input voltage which is our musical signal.
As the musical signal is compared to this rising wave, what happens is, and this happens very quickly, at little windows, it is just the higher the reference, which is our triangle wave is to the input signal, with high input signal wave, it just stays on longer.
So, in order to duplicate the higher output signal which is our music, which we want at the end of the day. We have a longer pulse or a shorter pulse and these happen like every hundred thousands of a second.
Class D amplifiers are very different than a class ab amplifier, which is more traditional. Little signal in, big signal out. It looks at the input signal, output signal for identical and every step of the way, it is making a larger identical signal. Whereas class d amplifier starts with an input signal and the output signal is, as I said looks like larger and shorter pulses.
These larger and shorter pulses than have to have their edges taken off which requires a filter on the output. So we wanted to shape the things with this filter and that what where we get into trouble with class d amplifiers.
Because this filter is a very difficult piece to design properly. So that it can actually power our speakers without changing impedance and without mucking up the sound. I have just posted a comparison chart for class ab amplifier vs class d.
Discussion with a manufacturer about Class D Amplifier.
Over the years, the designers have spent hundreds of thousands of design hours working specifically over these filters. I was talking to a friend at a manufacturing unit and he told me that basic class d modulators are the same as the one their company introduced in the hybrid class d amplifiers. Years ago they had their first class d amplifier in the market and it was a great sounding amplifier.
It used pretty much the same technology, the older work that is done is in the outer filter and trying to linearize the output so that it has very low noise. You don’t see much, it eliminates that switching which is on, off pulses that we have. These longer and shorter pulses, they are trying to eliminate those transitions because that can look like this 100-kilohertz noise. So that’s what most of the energy is going into.
Modern class d amplifiers, designed by good companies. I like BNO company and they manufacture true class d amplifiers that just sound awesome. They bring very neutral sound and we can control the way these class d amplifiers sound. The sound is set by the input stage.
Why People Avoid Class D Amplifiers?
There is a long history where class d amplifiers sounded like crap, hard and flat. Not that good but it has changed now. So today, big amplifiers companies are manufacturing class d amplifiers and they deliver just sweet awesome music. Now engineers have figured out the way, and with latest designs what you will get is only quality and awesome sound.
I would like you to try it, you will just love the way, these new class d amplifiers sound. What I say, is that these sound just awesome. So go ahead and try the neat music and you will always enjoy your decision of buying class d amplifiers.
Final Words: Class D Amplifier Disadvantages
So, I have explained every detail of how class d amplifier works and also added my discussion with a top manufacturer. The question that I received was Class D Amplifier Disadvantages and after writing this detailed article, I can firmly say that there are no major disadvantages of a class d amplifier. People ask about Class D Amplifier Disadvantages because they don’t know how this amazing stuff works.
Previously there were shitty designs and models of class d amplifier but now thanks to the modern designs and motivated designers, things have changed. Now you can only appreciate the quality that these class d amplifiers deliver. Go ahead and buy one and enjoy the music in its real forms. Read this Car Amplifier Buying Guide for more details.
Feel free to contact me if you have any questions related to calss d car amplifiers and I will answer your question in detail.
Team- Stereo Authority
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