I'm currently using a Bryston 3B-ST with my Model One Signatures with great success. The speakers sound dynamic, musical and authoritative with no hint of strain. Since the Model One's are a 4 ohm load, I would not recommend using the Moon I-5, they just do not deliver enough wattage. However, I did audition the Model One's with a Moon W-3 and W-5 amplifier and the results were just stunning!!