I've been able to play through the M900 for a few hours and it's an impressive amp. Really smart design in being versatile but very user friendly. You can dial in a good tone off the clean channel or dirty in seconds but still have plenty of ways to tweak the tone further. It responds to different basses quite dramatically. At first this was frustrating me but then I realized "hey dummy, the amp is versatile and not wholly imposing it's tone on the overall sound. That's a good thing". Then I started dialing the amp in with different basses and again this is pretty easy to do. I do find in general it sounds best with my active basses, definitely shines with a Spector bass so +1 to that list of a few of you here who have found the same. Really dig it with a Stingray too. From there I got the best results with brighter/hotter passive basses (P bass with EMG geezer sounds great, Lakland Glaub with fairly bright Fralin, P bass with Dimarzio Model P, etc.).
Unlike a lot of class D amps I've tried, the M900 does not have the "hollow" or "airy" mids feeling, it sounds to my ears closer to a class a/b amp. Yes, I know there are arguments about how class d does not sound different from class a/b and such but save those arguments for elsewhere. In my opinion, the M900 responds better than many other class d amps on the market in this respect. It sounds fuller to my ears.
The amp takes other dirt pedals really well and I was enjoying setting the drive channel on the amp to mild-medium grit and then pushing it harder with other drive pedals. Of course the A/O works well with the amp, but my fave so far with it is the Tech 21 GT2. The dear to my heart Brimstone XD2 also sounds excellent with the amp (no surprise there). I haven't started with fuzz pedals into it yet, that's coming up. Anyone have a favorite fuzz they're running into the M900 with good results?
I'm not one for "lighter is better" thinking when it comes to amps. I'll haul a heavier amp if it delivers the tone I want, but of course the M900 being lightweight is a pleasant bonus. I've not taken it to a gig but I imagine it's a nice amp to travel with for sure.
There are so many posts on TB from players wanting one drive pedal to pep up their rock tones, I think this amp would be very satisfying to that sect of players wanting to keep their rig simple and portable but be able to have both clean and dirty tones (I'm more the "turn on the dirt and never turn it off again" tone chaser).
Factor in the price and it's a lot of bang for the buck. I've got a mountain of amps I love and in some cases have been using for years but if I was starting out I'd say the M900 would be a great first (or only) choice. It's rich with the words ending in Y; portability, affordability, versatility, user friendly, bad ass-ability, etc.
Anyone using a B*K or VMT pedal into a similar sized/wattage class d amp should at least do yourself the favor of test driving the M900.
