DIY? How to get feet wet?

Just to clarify - the Bottlehead Seduction is a phono preamp. Their regular preamp is the Foreplay.

Hi,
Start with a kit that will result in a good sounding piece of equipment that you can live with for a while. E.g.: http://www.dynakitparts.com/store/product.aspx?id=2.
This is for a Dynakit St70. There is a huge amount of information about it on the Internet -- it has been modified extensively. After building the basic version, play around with mods to see if you like the sound changes.
By that time, your feet will be very wet! While doing this, read as much of the theory as you can find on the Internet. Most of the mod pages will also go into theory. More and more of it will sink in as you continue to read. If it's associated with a project or modification, you may see the practical application of the theory and it may make more sense to you.
Welcome to the world of DIY audio. It is so much fun. I am so satisfied when I complete a project and it sounds good! But, BE CAREFUL!!! Electronics projects expose you to LETHAL VOLTAGES! When you are probing circuit points with a volt meter, keep one hand in your pocket, literally. This avoids you providing a complete circuit path for the electrical current, and thus DEADLY SHOCKS. You can attach the ground probe to the chassis with an alligator clip.

Thanks for all the responses. I used to play in a touring band, and I would regularly fix cables, bias amps, and trouble shoot tube amp problems. Sounds like I could build one of these things if they are as point-and-shoot as they sound.

speaking of biasing, do these amps require biasing and other routine maintenance ?

I'm thinking of pulling the trigger on the 4 piece bottle head package with the line stage, phono pre, and dual mono blocks. I'm guessing these are about as introductory as it gets and produce good results.

Hi,
The St70 does require biasing adjustment. It is easy to do -- you just need a flathead screwdriver and a voltmeter (even the cheap portable one from radio shack will do).
I have any original Dynakit St70, and the bias voltage drop is read from a pin from a tube socket on the front panel. I am not sure where it is measured on the new kits, but it is probably the same. Or else, the instructions will tell you how.
Enjoy!

What is the likely-hood of one of theses things starting a house fire?

I had a nightmare last night that I raised my house to the ground after building a pair of mono-blocks and one of them caught fire while I was away at work.