[Arran]

I think this set would be completely useless for making into a pre amp, you could do it but it's like a shovel with a rope handle. If you want a tube pre amp either find an old factory built one or start collecting parts and build one from scratch. I often suggest pulling the tube amp out of a junked cabinet stereo from the early 60s, there are lots of those units around and most people can't even give them away if they are rough cosmetically.
Regards
Arran