The Rotel is enough power to make the bass but you could get more texture with more power. Better amps tend to be more detailed in the mids/highs and power seems to affect bass tonality in my limited experience.
I demoed the 802d on both Rotel and classe' amps back to back (also on AR tube gear) and it was not as night and day as one may think.
You may even want to look at wyred 4 sound. I like them a lot and they control the bass very well. They are dirt cheap and good, not just good for the money but actually good. Bryston also seems bright to me (at the very least neutral) and the 802d on the bright side.
Your issue sounds like a bass null too me for what it is worth.
I demoed the 802d on both Rotel and classe' amps back to back (also on AR tube gear) and it was not as night and day as one may think.
You may even want to look at wyred 4 sound. I like them a lot and they control the bass very well. They are dirt cheap and good, not just good for the money but actually good. Bryston also seems bright to me (at the very least neutral) and the 802d on the bright side.
Your issue sounds like a bass null too me for what it is worth.