Does an amplifier consume any power when nothing is connected? (GPD2846A built-in 2W amplifier)

Question

The GPD2846A module has a built-in amplifier into it. However, I want to use it with my headphones which don't require 1-2W (they are definitely going to distort sound and possibly be damaged). So I thought I could just solder the DAC-L, DAC-R pins (audio Left and Right output pins) and GND to a headphone jack and call it a day.

My concern is whether the amplifier wastes the 1-2W of power it normally would with a speaker connected (small form factor is desired so the battery is small and every mAh counts) even if there is nothing connected to it. I suppose if yes, I'll need to un-solder it from the board but I'd like to keep it there for future improvements so have that in mind too when answering please :)

There's more than one way to design an amplifier, and some designs can be _much_ more efficient than certain other designs. That module is so cheap, why not buy a few of them to play with, and measure the power consumption yourself? — Solomon Slow, May 02 '22 at 16:15

score 3 · Answer 1 · answered May 02 '22 at 14:32

3

"Does it consume any power": Yes.

"Does it consume the 1-2 W it would with a speaker connected": No.

It'll pull a tiny bit of power, though it's impossible to know how much without the datasheet for the amplifier. It won't consume significant amounts of power unless it's actually driving an output.

I doubt connecting your headphones directly to the DAC output will work very well, by the way. Couldn't say for yours in particular, but DACs aren't usually designed to drive a load directly.

answered May 02 '22 at 14:32

Hearth

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what does "designed to drive a load directly" entail? – user253751 May 02 '22 at 16:18
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@user253751 Sufficiently low output impedance. – Hearth May 02 '22 at 19:25
So what do you suggest I do to drive headphones? The first solution that comes to mind is a resistor but that would waste huge amounts of energy. – Παναγιώτης Θ May 03 '22 at 15:09
@ΠαναγιώτηςΘ No, a resistor would make it worse. You need an amplifier. – Hearth May 03 '22 at 15:28
So I should swap the 2W amp for a headphone amplifier? I'd like to have both headphone and speaker output so maybe solder them in parallel with a switch to shift from headphone to speaker amp? – Παναγιώτης Θ May 05 '22 at 15:19
@ΠαναγιώτηςΘ That would work. You can get 3.5 mm headphone jacks that have a switch built in that would let you automatically switch when you plug in headphones, too. – Hearth May 21 '22 at 16:30

Does an amplifier consume any power when nothing is connected? (GPD2846A built-in 2W amplifier)

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