Noise in Power Adapter. Will Filter Work?

We have a power adapter with these specs.
INPUT: I/P AC 100-240 V ~ 50-60Hz 1.5A
OUTPUT: O/P DC 15V == 4A A.V.
Power supply for our piano.

It hums when the piano is off and mostly goes away when the power is on.
When the piano is on, we hear humming in both the speakers and headphones.

(1) Could that be the power supply?

(2) Will a power supply filter work? If so, what do you recommend?

(3) Are there any brands of power supplies that really remove the noise better than others? If so, can you list them?

Thank you for your time.

Has the piano always had the hum problem or was it quite in the past?

The answer to that will determine if it’s a design deficiency or a component failure.

Hi Paul,

I don’t know when it started. Sorry.

The piano has 2 - 4mm TRS headphone jacks.

Same headphone in either jack and I hear the noise.
I tried different headphones and still hear the noise.

Changed the 3mm->1/4" TRS adapter to a couple others, and I still hear the noise.

I tried grounding the sleeve (ground) of the headphone jack with no success.

That tells me it’s not the headphones and not the 3mm->1/4" TRS adapter.

I tried plugging the piano into an APS UPS (uninterruptible power supply), and the hum is still there.

Any ideas you have are welcomed. I can get out a continuity meter, VOM, whatever to try to track it down further if that would help.

Warmest Regards,


That wasn’t my question.

I was wondering if it always had the hum or if the hum started sometime after it was brand new.

Your answer implies it did NOT always have the hum, is that correct?

The reason for the question is because if it always had the hum, there may not be any practical way to get rid of the hum.

If the hum started at some point later, it may be practical to fix the problem.

When I stated “I don’t know when it started”, that is what I mean. I could have always been there or started afterwards.

Thank you for your time. I can solve this with someone else.

Make it a wonderful day.

typo correction
"It could have always been there…", not “I could have…”

If you unplug the power supply from the piano, does it still hum? It still needs to be plugged into the wall.
Is the power supply warm to the touch when it is Humming?

If plugged to wall and not to piano, the power supply hums.

Power supply is not warm to touch after being plugged in all night and humming (piano off).

It’s a scratchy sorta hum in the power supply.

Also, the headphones do not hum with other devices.
And, the power supply output is approx 14.2 V and steady (not shaky).

The information is pointing toward the power supply being the problem. Here is a power supply from
MEAN WELL USA Inc. part number SGA60U15-P1J, Digi-Key part number 1866-4551-ND.
Click here for the Web Link
You will need to verify the output power connector to see if it is a 2.1mm X 5.5mm or a 2.5mm X 5.5mm. This is easily checked if you have a round toothpick handy. Insert the tip into the center of the connector, If the toothpick goes all the way in, then you have the 2.5mm connector. If only the tip goes in, then you have the 2.1mm connector. The power supply I offered has the 2.1mm X 5.5mm output plug. If by chance you do have the 2.5mm X 5.5mm output plug, an adapter is available to make the transition. Here is the adapter part number for the 2.1 to 2.5mm. Adafruit Industries LLC part number 2897, Digi-Key part number 1528-1731-ND to look at.
Click here for web page

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Thank you. I’ll look at those.
Make it a wonderful day! You deserve it.