As you probably already know, hifiman "attempted" to make a "quality" cable for the more recent cables, problem it is stiff AF, thick and really don't like to be bend at all. I Would really like to hear if there is a decently priced (sub 25 bucks Preferably, but I guess 45$ is still reasonable)...

I don't really recommend that type of an adapter, It puts to much stress on the 3.5mm connector, from both sides. I personally Used this in the past https://www.bhphotovideo.com/c/product/1063702-REG/sennheiser_561035_adapter_plug_for_hd.html It is so much more convenient and durable...

Hey, this might help you.   http://windowstipoftheday.blogspot.co.il/2010/11/windows-7-checking-usb-device-power.html   I got my F2 yesterday, and didn't have any success with My s7 on 6.0, G2 on 5.0, and my Nexus 7 running on CM14.1 with a custom kernel. tried a friends G3 on 6.0 and it...

  I bought my Fulla 2 2nd hand and I'm still waiting on the shipping so cant directly talk it, but I think I can explain your experience..  The HD598, being low impedance & having High impedance spike at the low end just sounds different while being plugged to high output impedance source...