I've used the KG3.5's with a 1 watt amp kit I built from Oddwatt. Does it peel paint off the walls? No it won't. If you are listening to jazz or concertos then 1 watt might be enough. If you are into Led Zeppelin and room shaking, ear-splitting volume then you'll want more wattage. My 18 watt/ch MIllett DCPP tube amp will drive my KG3.5's so loud that it is uncomfortable in my 12 X 18 listening room.