Worked well; went bad after six months of use
I bought a matching pair of these tubes back in June to compliment my APPJ PA1502A and they were great well they lasted. However, I'm sad to say after a bit of diagnosing the crackling problem I've been having in my headphones for the past few days, it's come down to these tubes being the issue. Now I'm back to using the stock tubes. I'm giving a 3.5 simply because of a short lifespan. After a quick search, 6V6 tubes should last around 1000 hours -- according to my Last.fm, in the year of 2016 I listened to 487 hours of music, and considerably, half of that should be from June until now. So they may have lasted a good 250-300 hours.