Do you already have a 70 watt tube amp that you want to continue to use? If so, what is it? If not, if you like the Cremona M, why not look for an appropriate tube amp for them? It is my understanding that the new Cremona are a lot easier to drive than the old ones. I have the original Cremona, but drive them with a tube pre and a SS amp. Have you considered this type of mix?