When I bought my first pair of 63s in 1980, I borrowed a Sumo Nine and a Berning EA-230, I kept the later, is was a great amp but I will stay with SS, nobody builds good quality tubes anymore notwithstanding the industry claims. I have an Electrocompaniet 100DMB and a Swiss Physics 6A but I do not need that kind of power. Again, I am just curious about the Aleph 5 not any other amps.