How do I get to Carnegie Hall?? Practice, Practice, Practice
How do I buy my first set amp? carefully, carefully, carefully
Sorry.(but true)
"What is the difference between EL34 and 300b". There are many makes of both tubes each with it's own voice. In addition, each tube can be in a differently designed amp so the variations are almost endless. Way to much to say here.
A big difference, in addition to sound, is power. All respect to Rockbox and the Bottleheads I cannot recommend a 2A3 because it is not going to be a good marriage with your new speakers that come in at a sensitivity of 94. You might "get along" in a small room at modest levels but the 2A3's will not sing at 3W. Why bother?
I will suggest a couple sites to look at. Paul Joppa, a chief Bottlehead, put together a little info at audioasylum.com in the FAQ section. He talks about matching amps and speakers for power and provides a nice formula. Take a look if you haven't already. One of the biggest mistakes is to underpower your speakers. Paul Joppa is very smart and seems to be a very nice guy too.
At Enjoythemusic.com they recently had a very nice review of 9 different 300b's. Nicest quick summary I've seen for a while on available 300bs (of course there are different opinions). Finally try Thetubestore.com for lots of info about the tubes you ask about and then some.
Also the "Secrets of Home Theater and High Fidelity" site has the best simple overview, about a dozen pages if I remember, of what a tube does that I have seen. Cathodes, anodes, grids, voltage, bias, AC/DC ect, ect. The name of the article is "Amplifiers" (Revised June, 2000).
If you want more sites drop an e-mail to me I have quite a few.
Geez it's late at night.
Sincerely, I remain