Connect 2nd DAC with fixed ouput volume to RPI with volumio

Audio Gear DACs
1

Hi Guys,

Have been using Volumio on my raspberry 3 + Hifiberry DAC+ quite happily… However, screwed down onto a piece of wood together with my Gainclone amplifier…

So it’s time to add a nice housing… To which i would like to add a couple of those old school analog VU meters they sell on aliexpress/ebay etc.
I would like those VU meters to respond to the music on a fixed volume level, separate from the actual DAC output that is fed into my amplifier (controlled by the volume setting in volumio).

I dont realy care about the quality of that output, it’s just for the gauges so i figured that maybe i can connect a 2nd cheap DAC to the I2S output stream used for the hifiberry and just let it decode to a fixed volume… I am however unsure what kind of signals control the volume of the hifiberry dac ?

is this done through i2c or is it embedded into the i2s stream ?

2

You could look at freshfoo.com/posts/raspberry_pi_vu_meter/….

3

Oh, that looks interesting ! should be easy enough… thanx for the link… now lets see if it responds to the dac output, or on the level before volume control.

4

Why not just configure alsa to copy the audio to both the dac and the built in audio output and use the headphone jack to drive the VU meters? I2s is sensitive to clocking issues so splitting it might give you trouble with your real DAC.

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