I just ordered a balanced TWag from Craig and he sells an adapter (which I bought) that is an RSA female balanced connector to 3.5mm Viablue. So you can just leave the balance cable on your JH Pros and then when you want to use single ended on another amp use the adapter cable to plug RSA male and female together and that is terminated with regular headphone jack.
My concern was spending the money on a cable I could only use with the Protector but now this gives me more flexibility.
Hope this helps
Is the adaptor still small enough it would be alright for if i had the viablue jack adaptor in my pocket plugged into my Walkman whilst on the go?