I've hade an MB115 (w/ tweeter) for about a year now, and I was very impressed at first. The quality is generally good--except I just noticed one of the screws that holds the amp part in the body is coming loose. That's what I get for putting it next to the Ampeg V4 I played on Saturday instead ... I bought it mostly because, at the time, I lived on a 5th-floor walkup and wasn't sure how often I'd be gigging.
Now that I leave it at the practice space, live on the 2nd floor, and am starting to gig regularly, I'm only about so-so on it. I'd have given the tone about a 7 out of 10, but then I played a set with a GK RB400 through some random 4x12, and then an Ampeg V4 through a matching 4x10 ... Apples and oranges, I know, but it has me wanting to trade up. I'd say I feel about 6/10 about it now.
The volume is mostly acceptable (I'm playing an outdoor show w/ PA support on Sunday; we'll see how it goes as a monitor). I found the tweeter to be very harsh, so I keep it turned off. Overall, the tone seems a little sterile. My "clean" sound, incidentally, is a Fender Japan 75RI J through a virtually noiseless DynaComp clone. It's missing a lot of the growl I expect from a J. That said, it can definitely handle some dirt and super lows--including blasts from my "psychedelic brown note" combo (MicroPOG + Sovtek Muff + Phase 90).
Maybe if it accepted an extension cab I'd consider keeping it when I upgrade.
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