Strange ALSA/Pulseaudio Bugs

Question

I have some serious issues with my sound on my xubuntu 14.04. Every 2-4 seconds my sound makes some noises. The volume bar in the top right won't stop showing volume changed to 100% and within 0,5sec to the level it was. My pavucontrol icon disappeared and if I start it from the terminal it shows "Analogue Headphones (unplugged) for 0,5 secs and changes back instantly, back to Headphones, back to speaker and so on.. When I uninstall pulse, alsa gives me some strange cracking noise.

What I did so far:

• uninstalled Pulse
• reinstalled Pulse
• changed the Alsa "Auto mute" to "disabled"
• bought new speakers
• unplugged my mic and every sound device
• booted into a live system (no errors)
• google'd for days..

Thanks in advance!

PS:

SYSTEM INFORMATION
    Running Ubuntu Linux, the Ubuntu 14.04 (trusty) release.
    Kernel version: 3.13.0-45-generic (#74-Ubuntu SMP Tue Jan 13 19:36:28 UTC 2015)
    GCC: 4.8 (x86_64-linux-gnu)
    Xorg: 1.15.1 (10 December 2014  06:15:52PM) (10 December 2014  06:15:52PM)

CPU INFORMATION
    Genuine Intel, Intel(R) Core(TM) i5-4570 CPU @ 3.20GHz
    Number of CPUs: 4
    CPU clock currently at 2900.000 MHz with 6144 KB cache
    Numbering: family(6) model(60) stepping(3)

MEMORY INFORMATION
    Total memory: 7895 MB
    Total swap: 7810 MB

HARDWARE INFORMATION
MOTHERBOARD
    Host bridge
        Intel Corporation 4th Gen Core Processor DRAM Controller (rev 06)
        Subsystem: ASUSTeK Computer Inc. Device 8534
    PCI bridge(s)
        Intel Corporation Xeon E3-1200 v3/4th Gen Core Processor PCI Express x16 Controller (rev 06) (prog-if 00 [Normal decode])
        Intel Corporation Device 8c90 (rev d0) (prog-if 00 [Normal decode])
    ISA bridge
        Intel Corporation Device 8cc6
        Subsystem: ASUSTeK Computer Inc. Device 8534

GRAPHIC CARD
    VGA controller
        NVIDIA Corporation GF114 [GeForce GTX 560 Ti] (rev a1) (prog-if 00 [VGA controller])
        Subsystem: Micro-Star International Co., Ltd. [MSI] Device 2384