I have owned a GK 400rb, a GK 700, GK 1001 and an Ampeg SVT111 Pro. All were good amps but the GK1001 had a power supply problem and kept stopping during gigs. The Ampeg sounded great but was very heavy. I now own a Markbass SA 450 and it weighs 3.5 kgs. Sounds great, has plenty of grunt and...