Amazon.com: gotor 4.4mm Balanced Replacement Cable for Sennheiser HD 650 HD 660s HD 600 HD 6XX HD 25 HD 580 HD 58x 7N Silver Plated Copper (1.2m(3.9Feet)) : Electronics
Custom Sennheiser Balanced Stock Cable For HD600 / 6XX / 58X / 650 / 6 – Corpse Cable
ZY Balanced Cable for HD 6XX Headphones & More | Audiophile | Headphone Mods | Drop
Got a custom balanced cable to take my 6XX wireless. : r/headphones