The bass at this point is very good... I played some Chesky organ music and it rumbled way on down with authority. I listened also to test tracks by Chesky with bass guitar... sounded very good. I listened to such a variety of music and test tracks and I honestly don't think the M2 has a real weakness. I want to see where it goes after about 150 hours with these stock tubes, then I will know for sure what I will be listening for with some good NOS tubes, or even some good new tubes. But, don't put these stock tubes down just because they are OEM's. I think the boys at Schiit like to send their stuff out so as to make a good impression with their OEM's. But, I know there is better... always is. Yes, I will be rolling!