Volume Pot and Helder AIO

[Lphillimore]

Hi @OrbitalPi

I think a few of us have been having this issue. Not sure it's the speaker that's causing your issue.

See last page on below Lounge thread for potential fix:

http://www.sudomod.com/forum/viewtopic.php?f=5&t=1185

[RxBrad]

I've seen arguments about grounding on the output of the PAM8403. Not sure how exactly you could do this mod on the AIO, but I include a couple caps and resistors before I merge the L and R ground coming from the 8403, and my two builds have had crystal clear sound.

Based on the second diagram here: http://www.chromo.cc/crate/crate-sound- ... -amplifier

Here's the crude drawing of what I've done. I actually use 4ohm resistors and 100uF caps.


I'm by no means an electrical engineer, so big grains of salt here...

[OrbitalPi]

Hey @Lphillimore

Thanks for the reply. That's actually really helpful

I have noticed that mine has different resistors on my board to the other ones people have posted. Mine have 1000 printed on them so I'm assuming 100 ohm?

I tried using an old laptop speaker which is 4ohm 2W and that seems to be worse that DS speakers for cutting out. I don't get any pops or cracks that are extremely loud.

I myself am using shielded wire as well. Hopefully the about mentioned diagram can shed some light

[Helder]

I have 4 filtering caps of 220pf to ground on each PAM8403 output going to the headphone socket but this is according to the manufacturer datasheet but might be the issue since all other board versions before this one didn't have them.

C18 to C21 are the caps and can be removed easily to test this theory without causing any major audio issues. Simply heat one side of them with a soldering iron and they'll come off clean.

[RxBrad]

For what it's worth, my experience is based on the PAM8403 clones from Banggood. (Side note: I just compared it to the manufacturer datasheet. Am I crazy, or did they seriously reverse the polarity on the outputs? I'm going to chalk it up to me not having a clue how PCBs work.)

[evillela2001]

Finally got my sound working at reasonable volume. Volume wheel barely does anything but it works. I have to set the software volume to 50 any higher and the sound starts breaking. For the fix I did the 2 75ohm resistors in parallel with the existing resistors based on what was on the last page a @helder support thread.

[OrbitalPi]

I have 4 filtering caps of 220pf to ground on each PAM8403 output going to the headphone socket but this is according to the manufacturer datasheet but might be the issue since all other board versions before this one didn't have them.

C18 to C21 are the caps and can be removed easily to test this theory without causing any major audio issues. Simply heat one side of them with a soldering iron and they'll come off clean.

@Helder Thanks for the reply so quickly

Last night I tried tapping into the "Left Out Speaker" and "Right out Speaker that you marked on the diagram below



That seems to have increased the volume ever so slightly and removed alot of the interference.

I did this with 2 3DS speakers I had laying about. I'm gonna try your above mention method and remove those filtering caps. Do they need to be replaced with jumper wires?

Thanks for al your help on this thread and the AIO support thread it's seriously very much appreciated

[Helder]

I'm gonna try your above mention method and remove those filtering caps. Do they need to be replaced with jumper wires?

Thanks for al your help on this thread and the AIO support thread it's seriously very much appreciated

No jumpers needed, just remove them.

[OrbitalPi]

So I've made a big balls up....

Whilst trying to replace R17 and R18 I've managed to remove one of the pads.....

Is there any work around here besides usb audio? If not its fine, I'll purchase a USB audio and working on it from there.

Posting this on the AIO support thread aswell