What are my options for voltage regulation?

I have a BPT-2 Ultra power conditioner that I am using in my living room system for all equipment. It handles everything pretty well. But I have a headphone amp from Germany (tubed) that is very sensitive to voltage anomalies, of which of course there are many at many different times of day. I have been doing some research into a power conditioner that provides voltage regulation and have read about the Monster, PS Audio (older and new Premier units), and, I think Exact Power units that can regulate voltage. Any opinions on these various units, or on others I don't know about? I guess I would sell my BPT Ultra if the voltage regulating unit can also condition power, but if there is a small unit with only one or two outlets that regulates voltage, that would be ideal. I haven't discovered any--have you?