611pro

With i play on 4-strings basses it's ok. But when i play on 5-strings basses sound disappears. All indicators on amp works but no sound. And i need to turn off and then turn on the amp to have a sound. It's just like as if triggered some protection on amp. :?:

Hi everybody !!!! I'll buy a new cabs and my choice is the 611 Pro. I'll use my tubepath 5.1 with, and I'm a little confused with the "impedance subject". Could you explain what the difference between the 6 ohms one and the 4 ohms one is? More power out ? Or for combine cabs ? Thanks...