Digital noise on TPA3116 - I2S DAC - Raspberry Pi combo

Twerp

Member
2013-12-23 5:05 pm
This is most likely a schoolboy error.

I've rigged up a little audio device that uses a Raspberry Pi and I2S DAC to feed into a TPA3116, but I'm getting awful digital noise through the amp output whenever the Raspberry Pi blinks an LED! The 19.5v supply is from a laptop switching PSU.

However, if I power the Pi/DAC with a battery power pack, everything sounds fine.

Have I wired this up wrong, or is the KIS-3R33S step-down board defective.


[IMGDEAD]http://s27.postimg.org/xkbisf4wj/schematic.png[/IMGDEAD]

Thanks in advance!
 

Twerp

Member
2013-12-23 5:05 pm
How about grounding the 0V of the PSU?

Currently, there is no ground.

Also check what gains you have. How much signal gives full output and is it simply a case of reducing the gain on the amp by turning it's pot down?
What can I ground it to?

I'm using a digital volume control in the pi software. So the gain is 26db i think.

Thanks!

Sent from my X5pro using Tapatalk
 

Twerp

Member
2013-12-23 5:05 pm