So, I picked up an old Telefunken Magnetophon 97 reel to reel a few years ago, and I figured its time to do something with it. The reels don't turn anymore, but the tubes all test good, so I thought I might try to salvage the preamps into something rack mountable. I found a pdf schematic (attached). Is this insane? Should I just salvage the tubes and put them in something else? I've done some preamp kit building before, but nothing with tubes. Any good resources out there for tube noobs?