Here goes; Last night I gigged my new GK MB Fusion 500 for the first time. ,ran it through my MB 4x10 standard. Bit O' tweeter on like I likes it. Played with my main bass (MM Bongofour). Full PA support. All settings at 12 o'clock. -14 Db pad pressed. I gravitated towards using my boost knob on my bass just a touch. It was very, very nice. I had the limiter on, contour switch at 800Hz, presence off, deep switch off. This resulted in an almost Tony Levin type tone. I focused mainly on using channel "A" in order to familiarize myself with this amp first time out. I did however use channel "B" for one song which was "My own worst enemy" by Lit. This resulted in the grind that is supposed to be associated with this channel. Very good indeed. Throughout the entire night, I did not need to fiddle with any of the controls/EQ! All colorations came from my Bongo. Very easy and likeable tone from the start. Gain "A" was at 12 O'clock, master"A" was at about 12:30. Plenty lound and concise. After the first set, i listened in on the fan. It was relatively noiseless. Although not silent. The amp still remained room temp to the touch. At the end of the night, the amp was warm to the touch well within reason. I love the orange-ish glow from the tubes. While performing "California Girls" by The lovely Katy Perry, I got to test a bit of the GK's slap sound. Again, very nice. Snappy and well defined highs. Present lows with thumb downstrokes. I was not looking to hear anything. No struggle at all. This was a medium-large venue gig. Compared to my GB Shuttle 9, the voicing is definately different. Seems to have a more defined mid range. Overall, I absolutely fell in love with the GK. I purchased it as a "back-up". It is an amazing piece of gear. Worth the money for sure. I can travel with both amps in one medium sized roller back pack. This also includes all cables, my wireless system, and other knick knacks. I will probably end up doing the bratty thing, and taking out whichever amp I feel that night!!! More to come as I use it more.