Installing blocking capacitor to block DC in volume pot

[TwoEyedJack]

Hello, I have an amp with integrated Bluetooth combo Board. It's powered by a 5s 18650 battery.
The issue is that there is DC going to the volume pot. Resulting in terrible noise and speaker for movement when attenuating the pot.
You can see a 6 pin connector on the left side of the board near the Bluetooth chip. That's the volume pot connector, it's pinout it Rin, rout, ground, ground, lout, Lin. You can just jump the in and out pins with a jumper. I can measure 1.584v DC between the jumper's expose top and the ground pin. I installed a bipolar cap 10μF 50v. But it doesn't seem to make any difference. The DC voltage does drop very slowly (it takes about 3 mins to go from 1.584V to 1mV) and when it does I can still hear the noise.

Any thoughts?

 

[Wolf]

I have the kab 230 amplifier in my little project and yes there is DC in the volume pot for sure. Whenever I use it and take the volume up or down, the drivers in the base range move either forwards or backwards respectfully. I do not know if there is a fix, but I am all years if you happen to find one. It seems like a capacitor should block the DC voltage, but I really don't know where I would put it to make sure that it worked properly. Good luck. My choice has been to just leave the volume in one position and use the source as the volume control.

 

[TwoEyedJack]

I have the kab 230 amplifier in my little project and yes there is DC in the volume pot for sure. Whenever I use it and take the volume up or down, the drivers in the base range move either forwards or backwards respectfully. I do not know if there is a fix, but I am all years if you happen to find one. It seems like a capacitor should block the DC voltage, but I really don't know where I would put it to make sure that it worked properly. Good luck. My choice has been to just leave the volume in one position and use the source as the volume control.

I've managed to block the DC, the volume knob now doesn't move the drivers. I just placed a bipolar cap 10μf 50v in series with the each channel of the pot. I will attach a picture.

That's not the biggest issue thought.
Probing around I came to the conclusion that there is no DC going into the speakers, so you are not going to damage them. Turning the pot acts like a signal generator hence the movement of the cone. I will propably end up not integrating the caps. Because my real issue is the bt noise.
Do you have noise when using the Bluetooth? In my case Bluetooth is very noisy, if I shut it off and use the line in, things are much better (there is still DC thought).
I am not sure if this is a bad design or my unit is defective but the noise floor is extremely high. Worse than any other cheap Chinese board I have tried. Maybe I will add a separate bt board.

 

[Wolf]

Yes, the BT is noisy on these, and I would only use it as a non-critcal apps because of this. Yes, direct connect is definitely better.