Bypass Raspberry Pi's USB Power w/ Tone Board

Some users are reporting that when the Tone Board is connected via USB-C cable to a Raspberry Pi, the Rpi’s HDMI-port will emit high-frequency audio noise (which for some people is really annoying).

According to our audio engineer, @Edison:

“The power supply for the Tone Board comes from your Raspberry Pi, and this current draw is always at a constant 350mA (independent of music playing, or not). We tested the USB-5V power supply of a Raspberry Pi with the equivalent load, and we found that the ripple interference voltage became very large: greater than 380mV. The source of the high frequency noise is the Raspberry Pi’s power chip. The good news is that our Tone Board has a filtering circuit, therefore despite the noise coming from the Pi’s power chip, the audio produced by the Tone Board is very clean.”

So this only affects other devices connected to the Rpi (not the Tone Board), that don’t have a filtering circuit. That said, if you wish to avoid using the Rpi as a power source, you can power your Tone Board via the 5V / GND pins on the GPIO, here’s how:

WARNING: DIY experience is required to perform this hack.

Tone Board works best when the input voltage is kept between 5-5.5V. Do NOT exceed 6.5V, lest you will see the magic smoke (and void your warranty).


the chip that needs to be eliminated, correspond to SOT23-5 or SOT563 or other?
Thank you,

hello, i’ve read quite a bit about powering the tonebard by the pinheader.
in other threads there is reference to the fact that powering from the pinheader Will trigger the board to reject usb power. here you suggest dessoldering the chip.
what should i do? what différence does it make if i apply this mod ? is this necessary? Will it be better? also i’ve seen the attached image. Will i need to fully dessolder the chip or only the first 2 legs from the left?

calling you tsangyoujun :wink:

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Hello @frenchadas, I’m not the technical expert on the Tone Board. However you can see this forum thread: Tone board : external powering

According to @gouwa, when power is supplied to the Tone Board from other than the USB-C, the USB-C input will be cut-off.