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Are Class D amps really 5 times less powerful than A/B?

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May 23, 2016
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When it comes to watts at least. Was watching a video with the President of Boss talking about the new Boss Katana bass amps. Him and the interviewer were saying that while the 60 watt 1x10 and 160 watt 2x10 amps sounded low in watts, you have to account for the fact that you need 5 times the watts for a digital Class D amp to match an analog A/B amp. So using Class D ratings equivalency, that would make the 1x10 a 300 watt amp and the 2x10 an 800 watt amp?
 
A watt is a watt, regardless be it tube, A/B, Class D.

The better question is are modern manufacturers fudging their power ratings?
I can tell you through the same 8 ohm cab, my old mark III peavey bass head is a lot louder than my Trace Elliot Elf despite them having similar power ratings (actually I believe the old peavy is less powerful at 8ohm than the trace is rated)
 
A watt is a watt, regardless be it tube, A/B, Class D.

The better question is are modern manufacturers fudging their power ratings?
I can tell you through the same 8 ohm cab, my old mark III peavey bass head is a lot louder than my Trace Elliot Elf despite them having similar power ratings (actually I believe the old peavy is less powerful at 8ohm than the trace is rated)

Is it though? A 50 watt all tube guitar amp is A LOT louder than a 50 watt digital guitar amp. A 50 watt tube Marshall guitar amp can be played at a large gig. A 50 watt digital amp? No...Its not even close. Why is that?
 
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Class D amps are not digital …

Is this a question of semantics?

Everything You Need to Know About Class D Amplifiers - Blog - REL.

Are Class AB amps better than Class D? If we’re talking about wide bandwidth for music through your loudspeakers, the answer is likely to be simply and definitively “Yes.” But when it comes to powering subwoofers, the answer is less clear cut.

How Do Class D Amps Work?
Class D amps, also known as “digital” amplifiers, work by shifting the sample frequency at which they operate up to extremely high frequencies. In doing so, they use MUCH smaller power transformers which takes up far less interior space—something that is always at a premium in subwoofers. In some cases, it saves almost 10% of interior volume, space that can go back into producing deeper bass and higher output
 
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Oh dear. Gee, if I read it on the internet, it must be right!

Here is a far better reference for understanding Class D amplification:
Class-D amplifier - Wikipedia

Worth the read. But, you will find nothing digital about it. BTW, that is actually the first or second reference that comes up on a Google search. I didn’t need to work hard to find it. Just sayin.
 
I'm only regurgitating words I've heard thrown around before so I could use some correction too if its wrong...

"Watts dont mean volume"

While yes it does take more power to push a larger sine wave that our basses produce, it doesnt tell us right away how that will sound to our ears and at what db level.
 
OK, so a nit to pick here, how is switching the rails on and off to simulate an analog signal not a digital process? What is digital if not having two states utilized to do very complex work?
That’s a fair question; but, if you take the time to read the Wikipedia article, it should clear that up. “Switching” by itself does not constitute digital operation; especially when the switched pulses are of unequal state. It is simply a bit more complex (and ingenious) of an amplification strategy, if a bit tough to get one’s brain wrapped around.

Bear in mind that a simple analog waveform is not just a simple sine wave, but much more complex, containing both useful components and wasteful non-useful components. The switching operation is essentially a clever way to keep the stuff you want and eliminate the wasteful stuff.
 
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The real question is does aged horse ever get tired of being summoned to these threads to sort us all out?
Yup. It might be a good idea to see if Andy could write a summary with useful references that could be stickied up above. That would at least provide an easily referenced thread for when these Q’s come up.

In fairness, Class D operation is not generally intuitive. The confusion is understandable.
 
Yup. It might be a good idea to see if Andy could write a summary with useful references that could be stickied up above. That would at least provide an easily referenced thread for when these Q’s come up.

In fairness, Class D operation is not generally intuitive. The confusion is understandable.
Like people read the stickies
 
I think the best answer is “who cares?” Watts are watts. The amplifier’s topology alone doesn’t determine its sound. The fact that tube amps were designed decades upon decades ago and voiced according to what they could sell and what they could design at the time has way more to do with the end product. If you are concerned about how much SPL a rig gets you, get more speaker and worry less about squeezing out all those elusive tubes and transistor watts.
 
digital Class D amp
Gosh, those digital class D amps again.....

I switched to class D amps a several years ago (Ampeg SVT 7 Pro). I don't see any single reason why I would go back to anything else. Same power, tone for a portion of the weight.
About the power: A 500W class D amps is the same as a 500W class A/B amp. Period
 
Only difference I hear between my old heavy Ampeg, and my new lightweight one is me laughing carrying my 500 watt combo(that sounds great) into a gig with one hand

Some people can't hear a difference between analog and digital, you are clearly one of those people. Im sure you prefer streaming music to vinyl too ;)
 
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