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Possible to spot class A/B or class D ?

Barry_Sound

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Hey guys, im still learning, please bear with me. Can you spot an amplifier class from just looking into it?
Here is an example, one is supposedly A/B, the other is class D. Same company, different model.

1030146-a3d88712-micromega-ia180.jpg[


micromega-ia-100-noir.jpg
 

Killingbeans

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Well, the top one has two Hypex UcD400 UcD180 modules in it, sooo...

And the bottom one looks like it's based on four chip amps of some sort that could very well be class A/B.

EDIT: UcD180, not 400 :facepalm::D
 
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B

Barry_Sound

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Well, the top one has two Hypex UcD400 modules in it, sooo...

And the bottom one looks like it's based on four chip amps of some sort that could very well be class A/B.
Thanks, so one would have to look for specific modules? The amp above is a French Micromega 180 btw. Below Micromega 100 which is supposedly class A/B (though not explicitly mentioned on the manufacturer site).
 

Doodski

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Hey guys, im still learning, please bear with me. Can you spot an amplifier class from just looking into it?
Here is an example, one is supposedly A/B, the other is class D. Same company, different model.

1030146-a3d88712-micromega-ia180.jpg[


micromega-ia-100-noir.jpg
Yes, we can almost all the time. It's not magic. After some electronics education and then some practical stuff one can see the tell tale signs of each type of amp. The top amp is class D as can be seen by the inductor at the amp PCB and the lack of heatsinking at the PCB other than the added silver heatsink. The bottom amp is using 4 ICs for the output amp stage.
 

Count Arthur

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The top one is Class D - I recognise the amp modules. :)

1643152605998.png



I don't think it's possible to spot the difference between Class A and A/B, but they will both have some output transistors, typically mounted to a heatsink:
1643153097120.png


1643153173368.png
 

Killingbeans

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Thanks, so one would have to look for specific modules?

This one was easy because the Hypex modules are so recognisable. You can also easily come across Class D amps that are built around chips from TI or designed from scratch. Like @Doodski says, a tell tale is that they have a low-pass filter on the output and need a smaller cooling solution for equivalent power output. They are a lot more efficient.
 
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Count Arthur

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For class D you would typically see a filter circuit using a combination of chokes/inductors and film capacitors.

1643155162874.png

1643155231610.png


Inductors come in a variety of sizes and styles:

1643154992026.png


As do film capacitors, but typically a little plastic box:

iu
 

MakeMineVinyl

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Just going by the two pictures and nothing else, I'd almost be fooled into assuming both were class A/B.
 

pseudoid

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Thanks, so one would have to look for specific modules?
Baris, these folks make the answers seem as simple as the question is basic. Don't be fooled!
Those count+beans+doods delivered your answer, but remember they are brainacs and they have to be able to FIRST dissect the innards (from decades of experience) to even determine which one of the various boards are the power modules...
Your best bet would be to just purchase the ClassD version, so that the environmentalist don't black-ball you for being irresponsible.
 
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