I highly recommend considering an Accuphase integrated amplifier. It combines the warmth and musicality of tubes with the control and drive of solid-state, making it capable of driving virtually any speaker with ease. Depending on your budget, the E-4000 (new) or a used E-280 (often under $5K) are excellent options. I personally transitioned from a tube preamp and 300B amplifier to an Accuphase integrated (E-650) five year ago, and I have no desire to return to a tube integrated or separates.
My next move, if anything, would be toward Accuphase separates. I truly consider Accuphase a lifetime brand; one you settle into rather than continually upgrade away from.

