what is a good wattage for a bass combo amp if you want to use it for shows? i currently only have a 15w ibanez amp and i need to find a pretty cheap amp that i could use in a band i might be joining soon (plus i need an upgrade anyway as my other amp sounds pretty awful now).

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You can mic just about anything, but I'd go with 100 watts and up if you're going through the P.A.; 200 watts and up if you're not. A lot of it is going to depend on your band. What kind of music do you play? How big are the venues? How many guitars does your band have? What kind/sized amps do they use? How loud is your drummer?

If you are playing through a 200-watt 1x15 combo and your guitarist has a 100-watt Marshall stack; you're going to be seriously outgunned. If your drummer plays louder than an artillery barrage, you'll be drowned out from the start. It is all relative; you see.
"Maybe this world is another planet's hell?" - Aldous Huxley
I used a combo for a long time, but I never want to go back. HEAVY! Also most combos are say 200-300 watts at 4 ohms, but have a 8 ohm speaker and require a extension cab to run at the full power. Also heads can be picked, then a cab making it more customized to your preference. A good efficient cab, and a good 200 watt head can go a long way. I have a GK MB200 head and a couple 1x15's.
I used to gig with a 350W SWR Black Beauty as stated above they are heavy.

I highly suggest getting a separate head and cab.

OH and I suggest getting at least 400w just for some insurance.
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