If you are in a suburban single family home and your power is good, you need a good surge arresting system not necessarily a power conditioner.
Be careful of transformers. Unless they are rated for high wattage your amplifier can be starved for current. High power (>1500VA) transformers are heavy and expensive. People with reasonably good power will not get significant benefit from these devices. High end amplifier companies like Krell, Bryston, Levinson recommend plugging their amps directly into the wall.