Class D amp board 1200Hz noise

[Yayoming]

Hi guys, I have little class D board as can be seen here:

Would like to use it bring back my dead Edifier R1280T (already turn in to passive speakers) and add some sub. Was using little class AB board but not sub output. Unfortunately after playing sound amp noise floor jumping up and there is 1200hz noise with harmonics going out of it as can be seen here:

(there is probably 60Hz noise but my phone mic do not pick sounds under 100Hz)

Any idea if board can be saved or need to look for some other project? Stereo potentiometer control volume of that peak, all way down that sound is still in place.

Thank you for looking and any suggestions.

 

[iMickey503]

I'm not an expert. But from everyone else that has reviewed these boards? None of them are winners. They all have some serious cost-cutting measures that make the amplifier boards pretty much incompatible with anything else but portable boomboxes.

There nice for power. All the parts are good like the chips. But its the little things they skimp on that make them not really worthy of being used for a build if you want S.Q. and a very low noise floor.

Its not that the chip is bad. Its the implementation of it.

There are some great Modifications to your board on the DIYAUDIO forums that go in to Razor fine detail on how to modify these boards for better performance and to get rid of the bottlenecks / drawbacks of the original board design and components. Noise being a major factor.

I however thing it is a ground loop issue. They seem to be made to work on battery power rather than a power wart. So that might be part of the issue.

Also, this might be a drop in easy fix at $20 bucks:

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[Yayoming]

Thank you for your input, think will look at diyaudio but most likely need to replace it with something else. Much appreciated help.

 

[antcollinet]

What is connected to the input when you are seeing the noise?

 

[Yayoming]

What is connected to the input when you are seeing the noise?

Hi, battery operated device like phone or tablet. Thanks