I was an octave MRE 130 with Super Black Box owner for years. I was driving B&W Nautilus 800 with great synergy. The B&Ws were 89db efficient. When I lived in Germany, Octave would host an Octave forum at the factory and we would all meet to discuss our equipment and all things Octave. Many folks in Germany who part of that forum in Germany pair Octave with Dynaudio and greatly enjoy that combination. Might be a clue as to what others who own Octave are using.
I agree that the V70 with Super Black Box would be the minimum Octave product to match with your Dynaudio speakers if those are the speakers you plan on keeping for a while. If you like the sound of your Dynaudio X34s, then experiment with these other amps if possible to see what matches and synthesizes with your tastes. Otherwise, roll the dice and see if like them.
I have since went in an entirely different directions with my system. Sold my Octave and B&W and now own McIntosh MC2301 paired with Classic Audio Loudspeakers T1.5 reference. I am done.
Good luck.