Here's what I suggested, please read carefully and don't overdo anything to avoid damage!
Problem:
Intermittent sound on USB, USB disconnects when moving Mobius USB cable.
USB doesn't connect with iPhone CCK.
Reason:
A.: Bad or insufficient contact making in the USB connector located on Mobius OR the source.
B.: Assumption: Charge current is on the edge of maximum for some devices, leading to problems in combination with (A.).
Can be tested by switching off charging on Mobius (long hold on volume button).
@KMann , AUDEZE team: I suggest investigating this point and try reducing the charge current by 10% in case.
Possible solutions:
iPhone/CCK problem needs using the bigger Apple 12W PSU in some configurations.
Improving contact quality:
Preparation: SWITCH OFF MOBIUS.
1. Get yourself a high quality contact cleaner (not WD40 or Kontakt 60) like Teslanol T6:
https://smile.amazon.de/TESLANOL-Ko...UTF8&qid=1540725500&sr=8-11&keywords=Teslanol
Apply very little, using a wooden toothpick, to the contacts of Mobius USB C connector and to the contacts on both connectors of the USB cable.
Don't spray on it!!!
If contact cleaner doesn't help execute the following test:
Cut a fitting peace from a THIN blister packaging and stick it in one side of Mobius USB C connector before inserting the plug.
That should improve clamping force and reduce " rattle".
If this helps, go one with:
2. Very slightly bend the 2 tiny clamps inside Mobius USB C connector (on the pad side) to the inside using one or two ( from both sides) sewing needles.
This improves clamping force. Don't overdo it else they will be bent back as soon as you plug the connector.
3. If this doesn't help either try bending the exterior USB C housing using fine blades to enhance clamping force.
Avoid leaving traces on the plastic parts.
You can use an old style razor blade, break it into fitting pieces and stick two pieces between plastic and metal.
Don't cut your fingers, use pliers for this.
Then use a normal fine knifeblade between those to very carefully enhance the pressure on the USB C exterior housing until it bends VERY slightly.