Hi,
besides the mechanical Problems. Is it possible to connect a 2nd HiFiBerry card (DAC+) to get two extra output channels. Are there GPIO Pins free for this?
I was looking for a delay. While doing this i rediscoverd Zythian and i ordered the new v3 kit. (Hope it ships soon 
)
I got a HiFiBerry coard from my first tests wif Zynthian. Now with the Audioinput i want to have one output for the synths and one for effects
Greeting Jens
I haven’t dare ask !!!
Basically at the moment no. Mayby not so much as it’s not possible as it disrupts an awful lot of what is going on in the guts because … assumptions.
That’s not to say it can’t be added, indeed I’m sure I’ve run a usb audio in on an audio injector ,machine and managed to hear a little bit of audio before usb crashed… . 
so the machinery on input ( and one would assume output) is down there…
I’d love it cos with an ADC DAC and a hifiberry amp you have a portable digital low latency class-D pa system with a zynth side order and almost unlimited effects processing!!!
It’s not possible to have 2 Hifiberry soundcards working on the same system. There are several reasons for that:
HifiBerry (and other similar soundcards) uses the I2S bus for audio data. AFAIK, I2S bus can’t be easily shared by several devices and drivers.You can send the same audio stream to 2 different DACs, and use the same clock, but not having independent audio streams.
Hifiberry uses I2C for configuring and controlling the device. The I2C address is hardwired in the device and hardcoded in the driver (although this could be easily changed).
Kind Regards,
Definitely time for zynthian cluster! 
I’ve have done some tests on this and it’s not so far … 
This is great !