Built by a group of dedicated engineers, AOpen has allowed the creativity of their designers and engineers to bring the plain AOpen AX4B-533 to a higher ground. Normally, such radical ideas would have been thrown right out of the Product Manager's office and never been heard ever again. However, the idea to integrate vaccuum tube amplification was not only received with enthusiasm, but was given the go-ahead to make it into a full shipping product. That's something very rare indeed and we should give AOpen a good pat on the back for daring to go where no manufacturers have gone before (ok, I'm a Trekkie fan). At this kind of economic climate, it's very daring of AOpen to pull this kind of stunt indeed.