Joeb, is your LS-15 with REL caps or InfiniCaps?
I had LS-15 with REL caps and it severely lacked bottom end punch. I replaced the caps with TRT Dynamicaps and it changed the sound entirely. It had more punch, smoother and overall more natural. The difference was substantial.
I now use ARC LS-25MkI(have to say that LS-15 with Dynamicaps come extremely close to LS-25 in sound) with X250.5 into N803 and it is very good. I use ARC CD3MkII cd player. All balanced cables. By the way, in balanced configuration you will get higher output from your LS-15 into Pass amp and it may improve bass output plus you will lower the overall noise floor. ARC is meant to run balanced. Also, before giving up entirely on the LS-15, if yours is with InfiniCaps(better version) try some NOS tubes if you are using stock tubes. Sovteks or EH tubes do not have very good bass drive.
Good luck.
I had LS-15 with REL caps and it severely lacked bottom end punch. I replaced the caps with TRT Dynamicaps and it changed the sound entirely. It had more punch, smoother and overall more natural. The difference was substantial.
I now use ARC LS-25MkI(have to say that LS-15 with Dynamicaps come extremely close to LS-25 in sound) with X250.5 into N803 and it is very good. I use ARC CD3MkII cd player. All balanced cables. By the way, in balanced configuration you will get higher output from your LS-15 into Pass amp and it may improve bass output plus you will lower the overall noise floor. ARC is meant to run balanced. Also, before giving up entirely on the LS-15, if yours is with InfiniCaps(better version) try some NOS tubes if you are using stock tubes. Sovteks or EH tubes do not have very good bass drive.
Good luck.