Cabinet for a class 5

Hey man if you just have the class 5 combo, I wouldn't bother spending any money on an extension cabinet because you're not going to get sound through the combo speaker AND the ex cab's speaker.  If you had the Class 5 head, I'd recommend a 2x12.

I've played my combo through a single 12" extension cab (celestion g12 65) and there wasn't much of a difference in tone.  It was a little better through a 2x12 (same speakers) but not much difference in the overall volume.  My advice:  If you don't have a lot of money then don't waste it on that cabinet.  You could also try and get another couple pre amp tubes to experiment with the amps tone.  Just my opinion.  -S

Well if you're looking for more headroom, you're not going to find it with 5 watts.  If you're going to lug a 4x12 out and about, you might as well get a larger more powerful head.

I played my Class 5 combo at an open mic already and I use it at practice with no trouble.  You're not going to compete with a large PA unless it's mic'ed and coming back through monitors.  But like the open mic for instance, I had it mic'ed (no monitors) and had no problem hearing myself with a drum kit, another guitar player (also playing small amp) and a bass player.  We weren't tearing the doors off the place but it held its own.

If you're dead set on an additional cab, I'd still go with a small 2x12.  To go to a single 12'' from a single 10'' speaker isn't worth the hassle.

Thanks guys!  I really don't play out often..I am just wanting to get some more head room from it.  I love the amp itself and have also had no problem playing it in smaller places and hearing it.  Just wondering if going to an extension cab and a lower pre amp tube will allow me to get some more clean head room.  The one thing I don't like about the amp is that there is no master volume.  I wish that they would have put a gain and master volume on it.  I dont want to lug around two amps, one for a clean sound and the class 5 for a crunch or lead sound.  I love the sound that it gets turned all the way up, but I want a cleaner sound with louder volume than when I have it turned to 2 or 3.  I thought that maybe a cab would help with that?  Maybe I should get a 2x12?  Any suggestions on an inexpensive 2x12 cab?

You won't get any more headroom with a 1x12, 2x12 or 4x12 cab so this would be a waste of money. 

Low gain pre amp tubes tip the balance of distortion from pre amp to power amp (SRV did this with 5751s) but you will still get distortion at high levels of volume.  You will get a bit more volume before it sounds as distorted this way.

Realistically to get a clean sound much louder you would need to mike it up the class 5.