If you look at the main picture, that device near the top of the board (between the DIN sockets and the cardedge socket) that looks like a VFD is actually the "tube" - it's some crap that Korg came up with a few years back, it's a low-voltage "tube" based on one of Noritake's Vacuum Fluorescent Displays. Vp can be 5V and Vf can be under a volt, like a hearing aid tube. It has lots of harmonic distortion for the moron that thinks smash clipping makes sound "rich." The other tube option they have looks like a real tube circuit, probably uses those shit sino tubes but it has a power converter on it, I assume to get a real plate voltage of around 150VDC.