Max for Live audio device working only in edit mode

Hello!

I am building a M4L device that should translate the audio input into a value in the range of 0-255, which will be used for controlling a DMX external. The problem is that the device doesn't work at all when attached to any audio or return track (in return tracks, it even blocks all sound), but when I enter the editing mode from Live, it works perfectly fine: the audio is coming in and flowing to the speakers, and the values are properly calculated. As soon as I close the editor and return to Live's running mode, the device plays dead again.

Might I be missing just something very basic?

Here's my patch:

Thanks in advance!