for the past five years i have been playing through a carvin PB300C 300W/1x15" combo. i have decided to give my amplification a long-desired update by buying a CROWN K2. i plan on buying a preamp and larger (i.e. more drivers) cabinet to complete my setup.
part of the reason i've decided to make the change is that i've played some gigs where the 1x15" just couldn't move enough air at 300W to provide enough clean sound for the venue. the other major reason is the carvin PB300C leaves much to be desired in terms of tone. (i played through a trace-elliot GPX12 preamp and got tones that usually take me a ton of tweaking to get close to, let alone achieve.)
who else uses a similar (preamp + power amp + cab) setup? who still swears by the combo amp?
are there any suggestions for preamps or cabinets (2x15", 3x10", 4x10", 8x10")?
thanks.

I use a similar setup. (preamp, power, cab)
infact, I just upgraded this month. I have never used the combo amps, I have always found them lacking in tone selection, although I have never played through a really high quality combo in a gig situation. My favorite (and current) cab configuration is 4x10 and 1x15. Pretty basic stuff. I have heard that an having only one cabinet With several speakers can actually weaken your sound, so I have always been afraid of an 8x10. Don't know if this holds any truth, as I do like the sound of the Megoliath. In the end it all boils down to what sounds good to you, because if you like it, you WILL play more musically. Good Luck.

Combos are good for smaller gigs, but they don't really have the goods unless you get into the high end stuff like the Metro or the Redhead.
I'm using a TC Electronics TC1144 preamp which kicks butt. It's solid state which I prefer for bass. Yeah I know tubes are cool, but personally I think they belong in the power amp, not the preamp. Anyway, the TC is 4 bands of full parametric eq. It will do anything. It's great as a DI too. I run this into the power section of a Trace 350RASMX. I used the Trace for several years and loved it, but....now I bypass the preamp and use the TC.
I've used Eden 210 XLTs for many years too, usually 1, but sometimes 2, however that will change as this weekend I'm getting a Bergantino 310! From what I've been told, that's all I'll need.

What type of rig you get depends on what you want it to do. I have really nice basses and I want my rig to amplify them without coloring the sound, but if I need to alter the sound, I want to be able to accomplish that with musical sounding EQ. I want it to be loud, clean and full range. I also want to be able to lift it into the back of my truck by myself.

I've also recently upgraded to components from a combo (SWR Workingmans 15), partly for more power and partly for flexibility. I picked up all the components used, mostly off the net. I'm using a Yamaha PB-1 preamp, Mackie 1400i stereo power amp and SWR cabs - a Son of Bertha 1x15 and Goliath Jr. 2x10. This combination of cabs (1x15 +2x10) seems to be getting very popular, and I love the sound I get from it. I like being able to mix and match - sometimes use the full rig, other times just bring the 2x10 and put it on a stand as a stage monitor and run my signal through the PA mains (w/ 2 -18" subwoofers). I still have the combo, and can use either of the SWR cabs as an extension speaker with it. I am starting to run out of room for storing all of these boxes, though.....

until this past weekend, i had never played through tubes. this weekend was also the first time i was able to get my J to sound like tim commerford on rage's "people of the sun." i instantly understood what was missing from my sound (2 to 3 percent of low, even-ordered harmonic distortion!). of course, the tube sound was too thick for some of the sounds i'm going for, where solid state is the way forward.

but that's what i liked about the trace -- i could get both sounds. and i would consider a different power amp, except that i still love how the K2 sounds, and i got it for so cheep that i couldn't refuse (70% off of list price!).

i've played gigs where my 1x15"/300W was just not enough clean power. i'd prefer to have more power and more speakers. and since i don't play out every night, i'm not so worried about size, though i should buy a cabinet that will actually fit in my ford focus.