Hello again,
is the USB-Power from a Pi4 “strong enough” for the ZEN DAC V2 as a HPA? Or is the additional power supply necessary? Maybe someone has tried it and can give a hint…
Thanks in advance and greetings from rainy Rhineland,
Achim
There’s no need for an additional powersupply, if you use the 3A PSU for the rPi.
Thank you!!
Please allow an additional question. Cannot find an answer myself.
If an external power supply is connected is there something like a switch-off in the circuit to drain power from USB?
Thank you an regards,
Achim
Can’t tell. No spare PSU available. Just putting the plug in, doesn’t switch-off USB. But I expect it would, as otherwise the PSU would blow.
Ran a test as my PSU came in yesterday.
When using the external PSU on the external voltage input, the DAC powers on in a different way.
Normally, when fed through the rPi, it powers as soon as the rPi powers up. with the external PSU, it powers on later.
So I assume there is a switch-off circuit.
Thank you again. I noticed (first time) a few hours ago that there is a tiny green led near the power input, which starts glowing when an external PSU is connected. Nothing said about in the specs. Or maybe my eyes getting more worse.
I’m waiting for an answer from iFi how things are.
Nevertheless, I am sure that it is an either/or. It would make absolute no sense.
Another and quite more interesting experience (for me): This little DAC is fantastic value for money. When thinking back a few decades 
it was never so affordable to have such great sounding gear.
Greetings from sunny Rhineland,
Achim
The DAC part is great value for the money, the amplitude control not so much. So I use it with fix output.
Maybe someone knows an album on Tidal which makes my new DAC’s
light shimmering Magenta… 
Not important, but I want to see it at least once 
Nice weekend everyone!