Very high crackle and noise on Boss DAC

[mothbhai]

I just got the BOSS, and set it up on an old RPi3 with RoPieeeXL and streaming via Spotify. Powering via an Allo Nirvana PS running off a filtered power strip. I am getting very loud crackle noise overlaid on the otherwise good music. The crackle seems to intensify with lower base frequency. When no music is playing, there is no crackle. With highs, it sounds like a bad interconnect contact issue. But with base music, it the crackle gets very strong and even feels like clipping/ overload. I have tried multiple interconnects and multiple amps - headphone and speakers - exactly the same issue. Also changed the PS to a regular Allo 5V supply. No difference - cant get rid of the crackle/ noise.

 

I can try to attach a sample of the noise. Will figure out how to do that.

 

Please help!

[mothbhai]

ok - might have some clue. The super cap on the bottom of the Boss was very close to the heatsink. I don't think its touching. But I tried prying it away from the board and the crackle has stopped. Wondering if I am the only one facing this issue with an RPi 3 heatsink?

[mothbhai]

on further close observation, the clip that connects the upper end of the super cap was touching the heatsink. In fact, it is not possible to fully press the Boss HAT fully onto the RPi without the heatsink pressing into the supercap contact. I am not using an unusual heatsink - the stock one that comes with the RPi. For now I have put 4 layers of electric tape on top of the heatsink to prevent any contact, and am leaving the HAT not fully pressed down and not screwed into the spacers. This is not a usable situation - as plugging in and out of the RCA contacts and any pressure on the interconnects can cause damage. So looking for advice from Allo. Should I use a different low profile heatsink? Or can I leave the RPi3 without a heatsink? This source will be on 24x7, so don't want to cause any heat damage either. 

[Audio_Allo]

On 2/6/2021 at 11:59 AM, mothbhai said:

on further close observation, the clip that connects the upper end of the super cap was touching the heatsink. In fact, it is not possible to fully press the Boss HAT fully onto the RPi without the heatsink pressing into the supercap contact. I am not using an unusual heatsink - the stock one that comes with the RPi. For now I have put 4 layers of electric tape on top of the heatsink to prevent any contact, and am leaving the HAT not fully pressed down and not screwed into the spacers. This is not a usable situation - as plugging in and out of the RCA contacts and any pressure on the interconnects can cause damage. So looking for advice from Allo. Should I use a different low profile heatsink? Or can I leave the RPi3 without a heatsink? This source will be on 24x7, so don't want to cause any heat damage either. 

Forwarded PM please check