I'm wondering if the problems I found with a 50 watt Sovtek Bassov tube head are common, or are unique to the unit I tried out yesterday. Basically, tone was fine until I turned it up to about 75%, then it sounded like the amp was overpowering the speaker, really farting it out. It didn't sound like a preamp overdrive. I tried the amp with SWR and Trace Elliot 1x15s, an SWR 2x10 and a carvin 8x10, all rated at 200 watts or more. Cabinets were impedence matched. What experiences have others had with the Sovtek bassov?