I'm in a band and our band is having a gig over the summer. The only problem is the guitarist has a 15 watt amp and I have a 10, so we need to upgrade. He is deciding between a 25 watt Fender and a 65 watt Crate. I need to know what the minimum watt amp I should get for the two situations. Thanks!
IMO get him multiple sources recommending a SMALL, LOW WATTAGE, expensive, "boutique" guitar amp.
That way he will be limited in volume and will be out of $ for upgrades, and therefore you wont need a 4x15 stack to be heard.
That being said, the type of gig really matters here. What matters more is the presence and correct use of a PA system.
for example, I did a gig a couple months ago with a 1x10 cab and a 400 watt amp. It was turned up to about "3", which is lower than rehearsal levels. I was DI into the board which was being run by an experienced guy. In ear monitors. The tone in the house, on stage, and in my head was really great. Great mix. Loud, small bar.
Recent gig. same amp, same setup, different but equivalent bar. This time we ran the board ourselves, so we were without the soundman and without teh PA subwoofer. I was retweeking my amp, had it running pretty hot, and was at the point of pushing my tough ole 10" speaker to the limit, and from what I could tell my House volume was lacking. I also found my stage volume lacking.
The PA is where its at, and whoever tells you otherwise is inexperienced or stupid (or has an agenda).
So, bottom line, it depends.