Hi there,
I just wired up my 3rd up2stream2.1 board and got surprised with a huge “plop” in the speakers everytime I connect the battery to the device.
I know them plopping slightly when disconnect power, but on connecting power my other 2 boards make no sound until some content is being played or the internal voice is telling me “connected to your wifi network”
Its the only board that does this loud sound while switching on.
I forced updating the device via API command and its now on latest alpha from raokit.
I did factory reset before and after the update.
No change of that plopping behavior.
May I have a faulty board?
On visual inspection the board looks fine.
Thanks for nothing but I share the solution anyway.
I spotted an additional 10k resistor on my good working boards which the newer boards dont have.
Adding this and popping is gone.
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Hi, how did you found the correct way to fix this? Did you reverse engineer the old and new PCB? Fascinating! 
@zpl1025 Can you somehow acknowledge this is the right fix? I have two boards which also try to trash my subwoofer each time I attach power. I could apply the same fix to my boards, but maybe you can tell us why you removed the resistor and nothing will be broken when we add this resistor back.
Hi, this is the right fix, before we soldered this 10K resister manually to fix issue. And should have updated the PCB for the future orders, could you check the date on the PCB? so I can check it.
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Hi, thank you for your reply! I will add the resistor in the next days, I think a 0603 will fit.
PCB date is 2020-6-5 for the amp 2.1 v1. I bought two of them in the last weeks in Germany. Despite the old PCB date they came with firmware 4.6.415145.44, which seems to be the newest one available (they did no auto update on first bootup). On https://developer.arylic.com/firmware/ v35 is listed as latest firmware 
