I had a pair of Shuguang 6SL7G Treasure series valves in my Cary's until one of them started emitting a very high pitched squeal (not microphony). I pulled them out and put them in a drawer which was a shame as I thought they sounded very good indeed (better than RCA etc). Since that time I've been running a lovely pair of vintage Tung Sols bought from a member of this parish and have been very happy with their open airy sound, good bass but also a slight hardness in the mid. So yesterday for some reason I decided to try the Shuguangs and put them in - no squealing but also weak bass and a degree of confusion soundstage wise. Basically not how I remembered them. As they've been in a drawer for around 4 months my question is do they need running in again? Or is my memory fooling me?