Tube Based Amp

I have just started making my way into the headphone market. I have been using pretty terrible headphones up to now, but I have considered myself a budding audiophile for some time now, using only lossless audio, and I have started collecting better gear. I just made my first real headphone purchase, an Audio-Technica ATH-M50. The M50 is not hugely in need of a headphone amp, but my Zunes at the very least have some trouble pumping them up all that loud. I have started working on my own modified CMoy pocket amp, using an LME49710HA instead of the OPA143 he uses, as well as a few other changes. I found out a while back that somebody I know has a HUGE, and I mean absolutely humongous collection of almost new vacuum tubes. I had been into the idea of tubes for a while, but, as with most people just getting into the whole audiophile arena, its much too pricey. I'm simply wondering, is there any cheapish tube based headphone amp, that can be bought without tubes? I have tons, and I'm just guessing here, but, wouldn't that likely be the most expensive part of a tube amp? If not, are there any simple designs, or cheapish kits? I'm talking as cheap as possible. It doesn't have to be a great amp, but I really would like try out the whole tube thing.

Part of the issue with DIY builds is the power required. Usually a few hundred volts, and I have no transformers designed for that, and they tend to be quite pricey. I did find one real low power hybrid 12AU7/MOSFET design I quite like for its simplicity and the fact that it is only 12v. I might try to build one just to see what I think. I know I have plenty 12AU7's, as well as several other 12A*7 types.   

http://diyaudioprojects.com/Solid/12AU7-IRF510-LM317-Headamp/  

That would be it. Is that design known to have any problems or be particularly good. It seems that being one of only a few low voltage tube amps might be bad, but I would really love to stick to only lower voltages, simply because I have no transformers. I know in his article about designing the amp he did, Chu Moy talks about a 24v tube/mosfet design, but its quite a bit more complicated. I might look at that one too though.

Sean, I don't know what people here will say, but, from a technical standpoint, pretty much any solder will do. I prefer silver based, and I don't even know how easy it is to get lead based anymore, but either should work. You should always keep your iron tip clean. If you don't, your tip will degrade much faster, and it will be more difficult to use. Any modern solder is rosin core, meaning it has flux inside of it. If you don't have rosin core, I highly recommend you get some.

Heh, no, not at all. At this point, it may actually cost less than lead based. It doesn't actually have any silver in it. Its likely that if you bought it within the last few years that it is silver solder, and not lead solder, as places such as radio shack and such don't even sell lead based anymore.

Can anybody give me a list of some really good tubes for headphone, or even full amps? I have such a humongous collection, there is bound to be something great in there. I have tons of manufacturers, models, different types, even quite a few of those weird non-glass ones. Also, would a really old transformer with a 115v primary, and 6.3v secondary be useful for any specific tube? I found one of those.