Jitters with Raspberry and Volumio

Hello,
I would like to have yours comment or suggestions improvement on my Hi-fi chain.

Before, my Hi-fi chain was:

  • high quality music on NAS Synology DS212j
  • Audio player “Audio Station” by Synology (MPD)
  • USB cable: QED Performance USB A-B Graphite
  • DAC: Micromage MyDac
  • high quality RCA cable
  • amplifier: Marantz PM5004
  • speakers: Focal Chorus 705

It was perfect, the quality was very good.

But now, I have to move the NAS in the garage. I could simply extend the USB cable but USB norm limits the length at 5m because interference. I need of 20m and more. So I think to use Raspberry with Volumio and now my Hi-fi chain is:

  • high quality music on NAS Synology DS212j
  • ethernet cable (RJ45)
  • freebox mini 4K (Internet Service Provider box)
  • ethernet cable (RJ45)
  • Raspberry Pi B + SD card 16go class U1 + Volumio (MPD)
  • USB cable: QED Performance USB A-B Graphite
  • DAC: Micromage MyDac
  • high quality RCA cable
  • Amplifier: Marantz PM5004
  • speakers: Focal Chorus 705

But with this configuration, music has parasites or jitters like scrached CD or dusty vinyl record.

Whence can this problem?
Should we replace my Raspberry Pi by Raspberry Pi 2?

thank you in advance,
Christophe