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Will lower voltage damage the Amp2?

Niklas Carlsson

April 07, 2022 18:51

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Hi!

I'm building a battery-powered boombox and plan to use HiFiBerry Amp2 with a Raspberry Pi 3B along with a 20 Ah powerbank that has USB-C Power Delivery (either 12V/3A, 15V/3A or 20V/3.25A). In order to get the correct voltage from the powerbank I've ordered a USB-C PD to DC adapter, such as the ZY12PDN.

Now, I've read that the ZY12PDN momentarily outputs 5 V to the DC output until the correct voltage has been communicated using I2C, and then switches over to the selected voltage.

Is this a problem for the Amp2? I get that the device (probably?) won't boot until a valid supply voltage (12 V - 20 V) is actually supplied, but I just want to make sure that nothing gets damaged by supplying 5 V to the DC input of the Amp2.

 

Bonus question - I plan to use both channels for an active 2-way speaker where the crossover is running in the RPi. Woofer on one channel and tweeter on the other channel. The datasheet says that I can output 2x30 W, but what happens when the woofer wants more power than the tweeter? Are the outputs able to output e.g. 55 W + 5 W instead of 2x30 W?

 

Best regards,
Niklas

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2 comments

• 0
  
  HiFiBerry team April 12, 2022 04:31

  5V won't daage the Amp, but the system might go into an undefined state and the system might not boot.

  I would rather recommend to use just batteries with a power management circuit for this.

  Real power output is always lower on tweeters as high frequencies have less energy. The Amp only provides as much power as the source uses. If you do the crossover in software, this will be fine.

• 0
  
  wkrt April 13, 2022 08:17

  I am using a ZY12PDN between USB-C power supply and AMP2. Works fine.
  Though adding the HiFiBerry power controller didn't work, the ZY12PDN just shuts down after 0,5 which may be concerning.