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smsl sa98e: 3w power consumption...

terragonj

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Hi.
I bought an smsl sa98e. Class D, 160wpc and it comes with a 36V/5.0A power brick.
Out of curiosity, I hooked it up to a wattmeter. At about half volume (the highest I can bear)
the wattmeter reports less than 3 watts....
neither the amp nor the brick get even minimally warm...
How is that possible?

John

PS: I'm really not an expert on amps, but what I've described above seems physically impossible at those
specs (unless I bought a fake empty shell, albeit a very LOUD one :) )
 

Holmz

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Well 1 watt per channel would be poking out 90dB SPL… Peaks will be higher but RMS is low.
 

Loathecliff

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At about half volume (the highest I can bear)
the wattmeter reports less than 3 watts....
Don't forget that the ear hears logarithmically.
(I've assumed you were not listening to a continuous sine wave)
 

MaxwellsEq

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How many watts you need depends on the efficiency of your loudspeakers. If you have efficient speakers and you are close to them, then 3 watts will be all you need. But, what were you measuring? Were you measuring the mains consumption or at the speaker terminals? If the latter, your watt meter may not have enough bandwidth and may under record.
 

jae

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Use the "Amplifier Power Required" calculator. If you have fairly efficient speakers, they will not need much power especially if playing at lower volumes. Apart from speaker sensitivity, the practical amounts of power required can go up exponentially if your listening distance increases or you need to play very dynamic music and loud average levels and require big chunks of headroom.

Maybe OP will see this after three years...
 

Loathecliff

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Use the "Amplifier Power Required" calculator. If you have fairly efficient speakers, they will not need much power especially if playing at lower volumes. Apart from speaker sensitivity, the practical amounts of power required can go up exponentially if your listening distance increases or you need to play very dynamic music and loud average levels and require big chunks of headroom.P will see this after three years...

Maybe OP will see this after three years
Damn! I missed that! I blame Holmz. It's all his fault:facepalm:
 

Holmz

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Damn! I missed that! I blame Holmz. It's all his fault:facepalm:

Well I wanted to get some attention here.

@Loathecliff
My daughter is looking for an amp to power some speakers and I was looking at the SMSL, but we also moved on to the AIYAMI ($70) and the Topping PAs3 ($140),

I think we are looking towards the Topping, and maybe a 50V/5A power supply.
And whether any intermediate capacitor would be in the middle…
 

Kijanki

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Average music power delivered to speakers is very low - in order of few percent of peak power, unless you listen to sinewaves at full power. It is because half of the loudness is 10% of power, while music also has gaps. Of course it depends on the type of music - Jazz trio average power would be extremely low, heavy orchestral pieces a little higher.
 

Holmz

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Average music power delivered to speakers is very low - in order of few percent of peak power, unless you listen to sinewaves at full power. It is because half of the loudness is 10% of power, while music also has gaps. Of course it depends on the type of music - Jazz trio average power would be extremely low, heavy orchestral pieces a little higher.

In the context of 1W - that makes sense as it would give ~85-90 db SPL.

And… (In my case)…
Yeah I understand that… which was why I was thinking that a capacitor in between might help to buffer the DC if there are “big slams” sucking it out.
 

RayDunzl

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At about half volume (the highest I can bear)
the wattmeter reports less than 3 watts....

Power vs SPL estimation...

1648943871714.png
 

Loathecliff

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