Magnepan ribbons problems

I had MGIIIa also and only replaced one tweeter in 7 years, and that was because of a movie soundtrack clipping my 255watt a channel amplifier. Movies would melt the fuse adhesive and the fuse would appear good, but wasn't. Make sure the fuses you are using are fast blow, not slow blow and the correct size.

Also are you bi-amping the 3.5's without the external crossover? This can cause problems.

Low line voltage might be starving your amplifier when it craves the current.

My guess is you are popping tweaters because you don't have enough current. Think 4ohm and get as much power as you can afford. I used my ARC D400MkII to moderately loud without any issues and my EAD PowerMaster 2000 (800watts into 4ohm) was even better.

Look at Bryston, EAD, or some other high current 4ohm stable load amplifier and check those fuses.

I am a big advocate for fuse bypass, but in a case like your get high quality fuse holders and fast blow fuses of the appropriate value. You should blow a fuse before you blow the tweeter.

Have you ever replaced the tweeters or just repaired them? If you just repair them, try getting new tweeters from magnepan and make sure your fuses are right. If you have any other problems you have a big problem some where else. Do you use vinyl? a big static charge could potentially blow a ribbon. I have played my fuse bypassed maggies(3.6R's) incredibly loud and NEVER had any problems what so ever.

I have the same speakers. I listen to a lot of music, including heavy metal/hard rock, real loud, and I've never blown a tweeter. I agree with the previous posts. Check your fuse value, and make sure you have enough power. A clipping underpowered amp can actually do more damage than over powering.

I have 3.6's and have blown fuses rocking with a Spectron digital amp with 650 wpc available. It's incredible how it does not strain. But, to have the tweeters being replaced every couple of years I have not heard of. I am sure you have discussed this with the factory. I wish I had more to offer you except the thought that loud music might be a stressor.

Based on my experience, clipping an amp will blow those tweeters every time. Tons of clean power is the key to avoiding damaging those tweeters. I also agree with other posters' comments here that the fuse value should be checked.

I would not even consider powering Magnepans with less than 300 wpc (minimum) if I wanted to play them loud and not risk damaging the tweeter.