Does the "D" in Class-D amplifiers stand for Digital?

[Slaugh 10+ year member]

i see some people in my country saying so... is it true?

i always thought there were Class-D amplifiers and Digital ones...

what's the truth behind this?

thx in antecipate

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[dewitt88 10+ year member]

Not an expert but I thought class D = Mono Block

 

[ramos 5,000+ posts]

Answer to your question and more //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

http://www.bcae1.com/ampclass.htm

 

[joetama 5,000+ posts]

Digital Switching //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[Slaugh 10+ year member]

oh, so the D does, in fact, stand for Digital?

well, it sucks then, because i was taught by someone from this forum a long ago something quite different //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif

 

[helotaxi 5,000+ posts]

Class D is Class D because A, B, A/B, and C were already taken. The amp is not digital.

 

[denim 5,000+ posts]

Class D is Class D because A, B, A/B, and C were already taken. The amp is not digital.

//content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[helotaxi 5,000+ posts]

The only one I know of that might actually mean something would be Class T (run by a Tripath chip) and a Class H which *could* stand for hybrid but probably got the name out of sheer coincidence like the Class D.

 

[Slaugh 10+ year member]

now i'm even more confused

 

[n2audio 5,000+ posts]

what's confusing?

Yes, Class D amps are often referred to as digital.

No they are NOT digital amps.

The output transistors operate at one of two states - on, or off.

That led the marketing departments to start calling them "digital" because they know idiots with money will buy anything that's "digital".

 

[enzowho 10+ year member]

Yes, Class D amps are often referred to as digital.No they are NOT digital amps.

The output transistors operate at one of two states - on, or off.

That led the marketing departments to start calling them "digital" because they know idiots with money will buy anything that's "digital".

Well put.

Basically, class A, B or A/B amps uses a transistor and amplifies a small audio signal (the one that comes from your hu). The signal always remains in its analog form. A class D uses a pulse width modulator (PWM) to convert the audio signal into a high/low sequences. The transistors are switched on/off (which is more efficient then a, b, a/b operation). These high/low pulses contain the original signal (called the fundamental frequency) and lots of high-frequency signals. The signal is low-pass filtered and all the unwanted, high frequency components are removed. This leaves the fundamental frequency which is an exact replica of the original signal.

So, you can see where the "digital" term comes from. Its not digital, n2audio is right its a marketing strategy.

 

[helotaxi 5,000+ posts]

This leaves the fundamental frequency which is an exact replica of the original signal.So, you can see where the "digital" term comes from. Its not digital, n2audio is right its a marketing strategy.

It's not an exact copy, its a rough approximation. The higher the switching freq, the closer the approximation gets. The tradeoff in a high switching freq is a decrease in efficiency. Since efficiency is the only real reason to go with a Class D in the first place, this is not an efective trade off in a high power amp. The compromise is to limit the freq range of the amp to freqs where a lower switch freq will not fall into the usable range of the amp and the distortion will not be noticable. That this is the portion of the freq range that requires the most power and would see the most gain from an increase in efficiency seals the deal. The output of a Class D amp is actually a square wave. It is sent through an inductor or an output coupling transformer to round out the wave form and to filter out the switching noise.

 

[squeak9798 5,000+ posts]

Not an expert but I thought class D = Mono Block

No.

There are quite a few multi-channel full range Class D amplifiers, especially if you jump outside the realm of car audio and take a look at home audio. Class D is just the designation for the amplifier topology.

N2Audio and Helotaxi are correct.

Class "D" does not stand for digital. It was just the next letter in line.

Class D amps are not digital.

Marketing and consumer confusion has led to the gross mislabeling of class d amps as "digital".

 

[enzowho 10+ year member]

It's not an exact copy, its a rough approximation. The higher the switching freq, the closer the approximation gets. The tradeoff in a high switching freq is a decrease in efficiency.

True. The original question was if the d stood for digital. I figured I shouldn't go too in-depth:

 

[creyc 10+ year member]

D does not stand for digital, it's merely the next letter after C. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif