Yes, definitely an overall output difference. The .22s do only have the two EL84s, whereas the DC-3 has 4. The .22 will do fine in most small rooms, and will be plenty for rehearsals unless you're competing with a half stack turned up loud. The DC-3 is noticeably louder earlier on in the range, and has much more clean headroom. I beleive the .22 is rated at 22 watts, as the name would imply, and the DC-3 is rated at 35. Both these ratings are definitely conservative, and I defy you to turn up a DC-3 past 5 or 6 on the master with the lead gain at 7 or beyond.
When I was playing my .22, (and this is a long time ago now), I was in a trio, and we were playing 4 or 5 nights a week in rooms that held up to 200 people, and we were not micing things up. That should give you an idea of what the amp can do. I eventually started running it through a 2x12 closed back mesa vertical cab to fatten the sound, and the thing would kill any 50 watt marshall stack it was put up against - hands down - in terms of volume and tone. I wish I had never sold that amp.
I rarely use my DC-3 any more, but generally when I do I use it alone with no extensions in small rooms. That amp also sounds massive through a quad box, by the way. That's the one thing about these amps that few people talk about - if you use them as a head to drive a bigger speaker cab, they become totally different animals, and you will be floored by the girth of the output.
