Well, I bought both. I don't know why I need both, but I've got them. I've only played with them just a little so far. The 470 only came with six adaptors, but the CR31A has 21 all together. Neither one had a universal one with it, so I might have to make some.

The CR31 has an issue with setting the filament voltage. When I put the initial setting on say 6v and the fine knob is in the middle it goes to 7v like you'd expect, but turning it only goes about .2v either way. I can't get it down to 6.3v. Anyone know the trouble? Do you guys recommend replacing the caps on these before using them?