My MB15 was delivered today.
Build quality is excellent. Everything's socked down tight.
I was wondering about the amp's electronics having no air vents, but other companies have done it successfully (Acoustic and Peavey come to mind) so I'll have to assume its been proven to work under rough conditions.
With everything flat, the rig sounds excruciatingly lean and midrangey. Thank God for the contour knob. I cranked mine all the way up. That got me halfway there. The bass control is effective but only at the fundamentals -- still, you have to use it as an antidote to the amp's prominent midrange. It's the low parametric, though, that will get the job done and generate the most impact in terms of bass punch. That and the contour knob. No surprises there. The high parametric is useful at knocking down any remaining midrange that's still around that you don't want.
I'm not a slapper; I play dance (Stefani/Gaga) or C&W, "depending." So the tweeter is just along for the ride with my style of playing, and therefore the position of the tweeter level switch didn't affect my sound at all.
Compressor works really well. They've chosen sane attack and release times, so it does the job without shouting its presence from the rooftops.
Drive knob adds a bit of harmonic bloom to the sound. I liked it as long as I used it in moderation. With that and the unit's "midrangey" character, I was able to get a close approximation of an old 50W Bassman through its 2x12 cab. Well, at least close to how I recall those things sounding.
I was curious whether having to be so aggressive with the tone controls to get a balanced sound was due more to the tiny unvented box or to the amp electronics. So, I connected an ancient 1x15 vented Peavey cab with its original square-magnet driver. YIKES. Sub-terror. I mean, MASSIVE deep bass. So yeah, this amp's leanness is due entirely to the box. But I guess that shouldn't have been a surprise, since this amp's barely large enough to contain its driver.
An active bass or external tone controls would provide added benefit in terms of tone balance, but you can go only so far with that in a cab this small before you bust something at volume.
In sum, I am VERY happy with this amp. It's the size and weight of a small packed suitcase, which is the primary reason I bought it. It will go loud enough to get you heard over politely-played drums (but just barely). And yet, connected to an external and more-capable bigger box, it becomes a whole 'nother animal, and a far more-impressive one. This thing paired up with a deeply-tuned box and an efficient, premium driver would make a capable small-club rig, and you could still use just the amp itself for low-volume rehearsals and solo practice.
I think Carvin bulls-eyed this one. It's an intentional compromise, but in my opinion they executed it really well.
So I shall wait on other reviews. Thanks though craig, pretty thorough review there.
