Wanted to run my newly bought HX Stomp "off grid". Googling on the topic led me to these Ripcord cables - and they do work as advertised! Very convenient to have one less (power) cable to worry about! Audio sounds crystal clear to me, so power output seems "clean" as well. The only issues I had was related to weak powerbanks, so make sure you get one that outputs 2.4 A @ 5 V.
And to power a Stomp, get a big powerbank... I have a 20000 mAh model, which drops about 20% per hour when used with the Stomp.