Is this a class D amplifier? If so, what is the reason?

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umm, I dont think thats class D.

 

The outputs would be driven into saturation and then off like a switch so it would be class D . Give me a nice analog O/P stage anytime.

 

Many high power amps are class-D today. They are small, lightweight and very powerful. If they were analog then they would waste a lot of power, get too hot and melt.

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Uncle $crooge

 

But do they give you an output which is nice to listen to. All this recent bump bump stuff which I hear coming from inside cars is ideal for digital but it's no good for music. In Class C you're biasing beyond cut-off,more efficient yes but distorted.

 

You're missing the point, it's NOT a linear amplifier, all it does is switch between the supply rails - at a high frequency, giving a large squarewave output. This is then passed through an LC lowpass filter that removes the HF component, leaving (in this case) nothing. In use the audio signal is used to modulate the mark/space ratio of the squarewave drive signal, giving pulses of differing widths at the output - after filtering the large HF components are removed again, leaving the modulation to feed the speaker, which is a low distortion amplified copy of the original audio.

Distortion is certainly low enough for top HiFi amps, although linear designs are probably still slightly better? - but can you hear the difference between 0.01% and 0.005% distortion?.

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Well, its the OUTPUT stage of a class-D amp. Its missing a lot, such as the heart of the device, which is a PWM circuit (triangle wave + comparator).

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Class - D amplification can be very high quality, this Hi-Fi manufacturer uses it in some of it's models:

http://europe.rotel.com/products/specs/rb1092.htm

The technonlogy has more use in portable equiptment really, but very compact amplifiers can be produced using it. Imagine how big that 1000W amp would be as analogue, and how much heat it would produce.

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Angry!? I'm absolutely electrolytic!

Will have to make do with myspace now I guess...

 

they are never really going to be high quality, and you would be rather stupid to even attempt to use a class D for full range, for subwoofer duties, they are ideal.

edit: I have a 1000watt class AB amp, it weighs about twice as much as that one you linked to, but is the pretty much the same dimensions...

edit edit:
http://img69.imageshack.us/img69/1193/3ca2.jpg

thats a CD ontop of the transformer.

 

If you want to get into audiophile then you need to use VALVES, anything else is a poor imitation.

MOSFET's or BJT's do their best to mimic the characteristics of a VALVE amp but they do not do it perfectly, thus in saying you like a class-AB amp implies you are already accepting some distortion (be it so small that you could noty possibly notice it like Nigel says).

Once you accept that fact the benefits of a class-D amplifier cannot be passed up (and yes that is a class-D amp, although a H-bridge output would of been better, reference of return and all that)

Get the switching freq high enough with a dedicated low-pass (or even low-pass+notch) and I would challenge anyone to tell the difference from a solid-state amp.

you can get some very poor Class-D amps (people not spending the time on the needed filter designs) just like you can get very poor Class-AB amps (I cannot bring myself to listen to even a CD on an all-in-one midisystem)

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You're living in your own little dream world! - many top HiFi amps are now class-D, it's a highly respected and perfectly valid system (if done well).

My 400W+400W PA mixer/amp sounds great and is small and light, a linear one wouldn't sound any better, but would cost a LOT more, be much larger, and a LOT heavier.

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My Hi-Fi amp is one of thier class AB models, but I have no doubts that the class D units sound just as good. Your class AB amp is very nicely made, but it appears to need fans for cooling, unless they only operate at high temps? Either way, thier operation will spoil the low noise floor desired for serious listening. I think you'd have to hear a class D model against a class AB one of similar quality, i'd like to myself. As for valves, i've never really heard them either, but isn't the deal with them that they have more distortion and noise technically, but usually sound more "musical"?

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Angry!? I'm absolutely electrolytic!

Will have to make do with myspace now I guess...

 

Yes, high distortion, high noise, poor frequency response, but many people love them? - they sound OK, but I wouldn't want one. It seems more of a fashion statement than anything else!.

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It's a well known fact Nigel the ear can iron out a lot of distortion just as the eye doesn't see the spot flying across the TV screen.

I was brought up on valves so I'm a bit biased,if you'll excuse the pun, and my knowledge of class D is very limited so I'll bow out.

 

Valves (vacuum tubes) create 2nd harmonic distortion which sounds musical because the harmonics are octaves apart. When overdriven, valves clip gracefully.

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Uncle $crooge