Hi, Magnepan's advice sounds correct -- usually this happens when an amp is driven to clipping trying to deliver a sound level in excess of the amp's clipping point. The amps you mentioned would seem powerful enough for most applications. How loud do you listen; how big is your room, and how far away from the speakers do you sit? You might also consider that a component in the chain ahead of the power amps is oscillating in the high frequencies. What preamp and source are you using?? Perhaps you need to look at those components... I have heard that certain cables can make amps oscillate, as well.
Magnepan MG3.6rs and tweeter fuse blowin
I'm having trouble with my Magnepans. I keep blowing tweeter fuses. I've used a variety of amplifiers (Classe Cam 350, Bryston 4B St, and biamped Acoustats TNT 200s and on certain CDs like The Eagles When Hell Freezes Over Hotel California, the applause blows the tweeter fuses. I've even had to replace a ribbon tweeter. Does anyone know the cause or cure? Is this a design flaw? Just when everything is sounding great and the volume is just right where you want it, out go the tweeter fuses. Magnepan advizes that this happens with underpowered or overpowered amps on certain CDs!