Good morning,
I want to connect 2 different USB DACs to my Volumio Pi4.
Has anybody experience with an USB Switch? The DACs are both fired only by the USB port, so I fear it will stress the RPi if they are connected each to one different port of the Pi?
Thank you very much in advance for your suggestions and a few more greetings from Germany! Stay healthy!
If you want to connect 2 different DAC’s, you should connect them separately to the Pi’s USB ports. Using an USB switch will only result into issues, like drivers, volume control and so on.
If you switch the DAC you should switch in “Playback Options”.
I am not even asking, why you want two DAC’s…
Thank you for these hint. The solution you mentioned, switching in the options, is still my favourite one. Question for me as an absolute dummie in electronics: Is the “power out” at the USBs “strong” enough to feed two DACs simultaneously?
And the answer to your not written question is only…play instinct 
The Pi will most likely fail on the peak current, when switched on.
You might avoid this using DAC’s that can be powered external.
Had a similar. Solved by using a 5VDC relay, operated by the USB port. The relay switched the power to the DAC. In this case the power to the DAC was controlled by the Pi’s power switch.
Just to mess with you an electric schematic… 
Even I could read this layout 
To get it specified:
- is a Topping 10s (no external power supply without handicraft)
- is a ZEN DAC V2 (has an external power supply, which is used)
Now I decided to “build” a second Pi4 running Volumio. I am quite sure, this will avoid all issues.
Anyway, thanks a lot for your time.
sell the Zen dac, no comeption in comparision to the Topping
I read perhaps every review of the ZEN DAC. It is the V2, so I will in combination with Roon have the full MQA. I like the look, believe me or not
And together with balanced headphones I also like the HPA.
So, there is enough space beside my gear and I will choose the option with two RPis.