Hi, There's something I don't understand: Ampeg says their V4B-head is rated 100 watt RMS, produced by 4 Groove Tubes 6L6-tubes. But Groove Tubes claims that their GT-6L6 C Tubes are rated at ca. 60 watt RMS each. Does that mean, if the Ampeg V4B-head uses 4 GT-6L6 C tubes, that the overall power rating of the V4b is actually ca. 240 watt RMS? Maybe it's a stupid question, but are Ampegs power ratings systematically understated, so that they can claim to be louder than other bass amps? Or is there something technically going on that I don't know (e.g. positive and negative tube watt ratings ...60 watt-60 watt+60 watt-60 watt= 120 watt)?