These were the best tubes I tried in my LS16MKI when I had it.
https://www.upscaleaudio.com/collections/vacuum-tubes/products/matsushita-national-pcc88-7dj8?varian...
I tried a lot of different tubes with all my ARC gear. These are really, really good and aren't that expensive.
I was lucky and started buying tubes over 40 years ago when they weren't in vogue like they are now and were cheap. I have drawers full of tubes. Could probably retire on what they are worth now...
https://www.upscaleaudio.com/collections/vacuum-tubes/products/matsushita-national-pcc88-7dj8?varian...
I tried a lot of different tubes with all my ARC gear. These are really, really good and aren't that expensive.
I was lucky and started buying tubes over 40 years ago when they weren't in vogue like they are now and were cheap. I have drawers full of tubes. Could probably retire on what they are worth now...