How 'Green' is Class D compared to other amplifier classes?

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Depending on use patterns Class D is as least as energy efficient as Class A/B, increasing to much more energy efficient in cases of heavy use. (High Power many hours a day).

The assumption is this typical use pattern:

Idle On time: 4 hours per day.
Play 10W level: 2 hours per day.
Play 50W level: 0.5 hours per day.

Is this a realistic use pattern?

Assuming the above use pattern, the result is, not surprising that Class A amplifiers consume vast amounts of power:

powercon.jpg


Please comment.
 
frugal-phile™
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Lars Clausen said:
Idle On time: 4 hours per day.
Play 10W level: 2 hours per day.
Play 50W level: 0.5 hours per day.

Is this a realistic use pattern?

Probably not. At a 10W level you are likely going to be clipping a 100W amp with real music. And more & more 100W is a big amp (a really big amp if Class A). What happens when you consider amps of 10-20W?

How much power does a typical (hi-efficiency) light bulb consume in a year?

dave
 
Re: Re: How 'Green' is Class D compared to other amplifier classes?

planet10 said:


Probably not. At a 10W level you are likely going to be clipping a 100W amp with real music. And more & more 100W is a big amp (a really big amp if Class A). What happens when you consider amps of 10-20W?

How much power does a typical (hi-efficiency) light bulb consume in a year?

dave

Will depend of the level of compression as most recordings has restricted the dynamic range for many reasons.
If we don´t talk about live music (were limiters sometimes kick in
;) )

FM broadcasting;commercial radio=
:bawling:

BTW efficiency can be calculated or measured or both then compered.

http://www.amplifier.co.uk/images/Data Sheets/Class_D_Efficiency1-Ed-CFBAccept.pdf
 
Variac said:
It's also interesting that the big drop in consumption is between class A and the others- an order of magnitude.D is not radically better than class AB.


Thanks for your comment, you are absolutely right.

powercon2.jpg


Green Class D reduces the power consumption to about half in most use patterns, even this one, where the amplifier is always on, and only used a few hours per day.

This is of course not magnitudes of reduction.

But if you care about your CO2 emissions, and want to reduce your power consumption, this is one way to improve the situation without changing your use pattern.
 
In general efficiency means input of a resource/many resources in relation to a wanted output. The output need not be "good" or beneficial. After D-day the efficiency by German soldiers killing allied soldiers was higher for the Germans than vice versa, at least until the break-down of the resistance. (I do consider killing people a bad thing but this isn´t the point).

So if someone can´t enjoy the sound of an amp; can´t stand the sound of it, the resources put into building the amp or the electricity drawn is wasted and the efficiency zero in this case.

The need for power from an amp may vary with type of music and compression rate used, the size of the listening room, the acoustics of it and the efficiency of the loudspeakers and of course the sound pressure level needed. Some like Musical Fidelity's Anthony Michaelson claims that the need for high power amplification is generally higher than most people think of and power amps of about 2x500W and above should be the norm.

It´s possible to statistically study the content of a recording and calculate the need for amplifier power, (the presumptions given).
For instance it´s possible to calculate the need for no-clipping at all, for clipping occurring at 0.1 % of the time of a certain recording or for an acceptance rate of 1% etc. The conclusion might be that some type of music and certain recordings of it really needs some power to be faithfully reproduced, even if the average power is relatively low.

A "green" system should maybe be able to predict the need for power and adjust to it?
 
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