Mark, if you're referring to your audio equipment, no additional "line conditioner" should be necessary. The power supply sections of the units have transformers, rectifiers and filter capacitors which supply clean DC for operation, and the fluctuations which you mention are handled routinely. The AC which comes out of the wall socket isn't what winds up getting used. $450, or anything beyond $20-$30 for a surge protector strikes me as a waste of money.

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Enjoy the music, not the equipment.