Power problems with Raspberry Pi model 3B+ and Allo Boss DAC v1.2

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4. Oktober 2018 at 10:34 #38349

Hi,
I have encountered an issue when trying to power the Raspberry Pi model 3B+ from the Allo Boss DAC v1.2, i.e. attaching the power cable to the USB C socket on the Allo Boss board and powering the Raspberry Pi through the GPIO. I use ethernet cable and wifi/bluetooth disabled.
The Allo Boss‘ onboard power regulator seems not to be able to deliver the necessary power to the Raspberry Pi 3B+.

I am using a linear power supply that delivers 5.2V (5A) to the Allo Boss DAC. However, on the GPIO, I measure about 4.6V (which is too low). The power consumption is around 600 mA at startup, falling to around 500 mA in „idle“.

The low voltage to the Raspberry Pi makes it „unreliable“, i.e. sometimes the Raspberry Pi does not finish the startup process, because the voltage is too low, which is also confirmed on the monitor with „Under-voltage detection“.
I have tried with two Raspberry Pi model 3B+s; the issue is the same.

If I use an „old“ Raspberry Pi model 3B in the same setup, there is no problem – and the sound is wonderful.
The voltage on the GPIO is a little more than 5V (5.05V) and the power consumption 250-300 mA.

Unless any of you have another explanation, my deduction is that the Allo Boss v1.2s onboard regulator/filter is not designed powerful enough to power the Raspberry Pi model 3B+ via the onboard USB-C connector.

I would like to hear, if anybody else has experienced the same issues.

Have a nice day,
Anders

[Heiner premium]

Heiner premium

4. Oktober 2018 at 12:48 #38384

Hi anders,

We have not yet experienced this issue. Do you have any periphery connected to the Pi that might also require power?

Have you tried powering both devices individually? This is the ideal setup for best audio performance. For this, the jumper on the BOSS board needs to be removed.

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4. Oktober 2018 at 21:34 #38397

Hi Heiner,
I only have the Allo Boss DAC v1.2 and the Raspberry Pi model 3B+ connected to the power supply.
I will investigate the issue – also powering the devices individually – a little more and report back.
What puzzles me is that it is only the Raspberry Pi model 3B+ that makes „Under-voltage trouble“; I have now tried 3 boards with the same result.
I have now also tested 2 Raspberry Pi model 3B without any issues – only good sound – and much lower power consumption.
That is why I was wondering about the power regulation/filer on the Allo Boss board with a big voltage drop (more than 0.5V) from Allo Boss power input to the GPIO.

[Heiner premium]

Heiner premium

5. Oktober 2018 at 11:33 #38402

Hi dan,

The 3B+ does indeed need more power than 3B. Which is why we previously already made a blog post, detailing the changes of 3B+ and why it is not a necessary upgrade for most Max2Play users. However, with the BOSS DAC 1.2 and a sufficient PSU, this should not be an issue.