Comment 8 for bug 1265611

I can confirm a similar behavior as described in post #7.

1. I installed Ubuntu Studio 15.04 on the harddisk and there was no way to get sound from speakers.
2. I started Ubuntu Studio 12.04.5 from a USB stick with persistence and did all updates.
3. With 12.04.5 initial system and also after update I had sound on speakers.
4. I boot 15.04, with power connected, and there is sound on speakers.
5. I boot 15.04 using the battery, and there is NO sound on speakers.
6. I boot 15.04, with power connected, and there is NN sound on speakers.

7. I go back and can repeat cycle starting at item 3.

I also verified, that when just temporarily removing power cable before step 4, I still have sound in step 4.