Hey, I know there are some threads about noise problems here but I couldn't find the right answer.
I am building an amp out of an Fosi Audio ZK-502T Bluetooth 5.0 Amplifier Board (TPA3116D2 Chip).
...and I have some Issues with noise. Please hear this video for demonstration.
For some context:
The 1 khz Sinus sound you hear is on purpose, I needed some input signal because otherwise there is a noise gate turning on. So ignore this one.
First there is this white noise like sound in the background, might be normal is not that wild. Only audible at very high volume.
But then there is also this incredible loud buzzing sound. When I touch somewhere on the circuit (ground) it gets way more silent and when I come near the cables it gets louder, even before touching.
I am connected over bluetooth, so no input device is connected.
This is the board.
I modified it a bit to build it into my casing.
I desoldered all 3 potentiometers.
The volume poti also works as an on/off switch, so I bridged these two paths to have it always on. (Red small wire)
The other connectors I wired back to the potis to have them somewhere else in the case.
Before I desoldered the potis I think there was no problem of this sort. Only tested it shortly once before so not 100% sure. My guess would be some problem with the cables or the ON/OFF shorting.
Can you please help me figure out where my problem is?
Thank you!
I am building an amp out of an Fosi Audio ZK-502T Bluetooth 5.0 Amplifier Board (TPA3116D2 Chip).
...and I have some Issues with noise. Please hear this video for demonstration.
For some context:
The 1 khz Sinus sound you hear is on purpose, I needed some input signal because otherwise there is a noise gate turning on. So ignore this one.
First there is this white noise like sound in the background, might be normal is not that wild. Only audible at very high volume.
But then there is also this incredible loud buzzing sound. When I touch somewhere on the circuit (ground) it gets way more silent and when I come near the cables it gets louder, even before touching.
I am connected over bluetooth, so no input device is connected.
This is the board.
I modified it a bit to build it into my casing.
I desoldered all 3 potentiometers.
The volume poti also works as an on/off switch, so I bridged these two paths to have it always on. (Red small wire)
The other connectors I wired back to the potis to have them somewhere else in the case.
Before I desoldered the potis I think there was no problem of this sort. Only tested it shortly once before so not 100% sure. My guess would be some problem with the cables or the ON/OFF shorting.
Can you please help me figure out where my problem is?
Thank you!
Last edited:
"But then there is also this incredible loud buzzing sound. When I touch somewhere on the circuit (ground) it gets way more silent and when I come near the cables it gets louder, even before touching."
Looks like you may have answered your own question. It appears to be a grounding problem caused when you removed the potetiometers and soldered multiple wires in their place.
If I were you I would remove all the wires and start again. You need to be careful about desoldering these boards as you normally only get ONE chance before the solder pads and attached tracks self destruct. You probably have lost a ground connection/pad/track and there is not continuity.
When you have removed everytihing take lots of good quality pictures of the board where you removed the pots and both sides of the board.
Looks like you may have answered your own question. It appears to be a grounding problem caused when you removed the potetiometers and soldered multiple wires in their place.
If I were you I would remove all the wires and start again. You need to be careful about desoldering these boards as you normally only get ONE chance before the solder pads and attached tracks self destruct. You probably have lost a ground connection/pad/track and there is not continuity.
When you have removed everytihing take lots of good quality pictures of the board where you removed the pots and both sides of the board.
