I am not familiar with tube amps and i wanted to know what a pre amp and power amp is?

Also once i am old enough for a job and can afford stuff i want a stack. I dont gig or any thing just practice. I know people say that a 4X12 Cab and Head are for playing huge stadiums and whatnot, So if i got a half stack would it be way loud to play in my house? And If i turn it down it wont sound as good as if its cranked(I think?)

If a 4X12 Cab Is to loud could I get a 2X12 cab to make it more suitable for bedroom practice? cause if it has 2 less speakers It wont make me deaf.

you could always use an attenuator to make it not as loud (the quality of your tone after this seems to be up to debate though). Don't buy an amp just because it's a stack, there are some very nice combos out there.
my gear:
Epiphone LP standard
roland microcube
The pre-amp is where the signal from the guitar goes into and get 'flavoured' as it were. The power amp takes this new signal and pumps up the volume, amplifying it. Both stages can be done with either solid state transistors or valves.

As for speakers, the number of them wont make as bigger difference as the head units power output. A 100W 2x12 will still be louder than a 50W 4x12.

These stack you hear about don't fill stadiums, they're nearly always microphoned up or hooked directly to the PA.

Your comment about sounding better cranked is only really true for valve based amps, where the signal skews of in its top range giving creamy overdrive.

Yes you can own a half stack for your bedroom, some would say it looks silly and is definitely overkill. a 2x12 or even 1x12 is plenty. It's the power choice to be carefull with, 30W-50W is usually a good area to be around for SS amps and 15-30W for valve. This will give out sensible bedroom levels but still enough headroom for the odd pub gig with a drummer. If you just want natural overdrive then find a 5W valve and turn her up.... Will still be loud however.

- Rich
Yeah, I don't see why not.
Quote by Cathbard
If all you had to go on was the forum you'd think a Decimator could cure noise caused by dodgey stage lighting and restock the ocean's population of sperm whales
Or would this be an ok bedroom setup too?

Peavey 6505 or XXX or JSX an Avatar 2X12 Cab and an Attenuator (if needed)