Hello, Clemens. Thank you for your suggestion. I've found the problem last night when I killed the artsd. I used to start the artsd with jack right on the startup sequence to make kde use the soundcard together with the other sound applications (muse, ardour, etc). So, when I unloaded artsd, all worked very well. I recorded some tests and played it without any quirks. Then, I changed my script to not load artsd after jack. And I observed the rtc interrupt while playing with muse, but it keept on 0. So, I think that the setup is correct. Thanks again for your kind attention and my best regards. -- ------------------------------------------- Denis A. Altoe Falqueto -------------------------------------------