supply power to a chinese d class amplifier

[walker1234]

Hi everybody,

I had bought this amplifier from aliexpress some times ago the model is zk-mt21.
The amplifier accept a tension from 12 to 24 volt for supply, as you can see in the image there is a 25 voltage electrolitic capacitor.

The problem is that I want to give supply from two lead acid battery and the voltage of the battery can go from 23 when empty and 27 when charging from the solar panel.
I connect my amplifier to a 22volt power supply and I see that rarely it consume more than 1.5 ampere continuosly.

I want to use some 10A diode in series of my amplifier to lover the voltage for that 3 volt.
But every time I search for lower voltage with diode everybody become crazy because of inefficienty.

I know I can use a dc dc converter for lover the voltage to 18 volt, but I want my setup to be simple, and a step down that can handle 10A is a bit too much for that.

Everyone have some suggestion? thanks

[tom66]

Replace the 25V capacitor with a 35V one?

You would need to make sure the electronics inside can withstand 28V, but chances are they just cheaped out on the capacitor and selected the closest one that met the requirement of 12-24V input.

[mariush]

Open the lid and see what actual chips are they using , and if they're using voltage regulators. 

It's possible the amplifier chip supports higher voltages in which case you wouldn't need to add diodes, you'd just have to replace those 25v rated capacitors with capacitors rated for higher voltage.

[walker1234]

the amplifier chip is a CS8673E i attached the datasheet, it seem like the chip can handle 26 volt max.
Maybe I can use a 50V capacitor instead an connect directly the voltage supply

[retiredfeline]

Or just buy a new class D amplifier that can accept higher supply voltages and save this one for other uses. They are so cheap these days.

[walker1234]

I just take the suggestion from retiredfeline, and bought the model zk-ht21 more powerful and can handle up to 36v.

I fell safer like that, instead of use the amplifier at the maxium rated voltage.

thank you all!