Blown tweeter fuse, but it was only 1/2 amp & fuse vs ??

Of all the oddities, I blew the fuses on my monitor 5A's with a 150 WPC 8ohm Krell i300 with the highest WPC (on paper) and the lowest DC offset that they have seen. The fuses were 20+ years old, half the 1amp recommendation. I am not sure if that is a factor or not, or there was an issue with the Krell. The speakers spent most of their life driven by a vintage Kenwood KR-6400 that had no issues driving them. My Hafler DH-220 didn't have any issues either. Both had decent reserve power, and higher DC offsets.

I pulled out some old rock CD's from the 80's while doing some listening to the Krell, comparing some speakers, and trying to get a baseline before some crossover upgrades. At one point something sounded a little off, the bass seemed to disappear some. The Krell was not super hot, but what I would expect for a Krell. I was listening to the SDA's at the time so I checked all the cabling. It was fine. I decided to connect up to the monitor 5's since that is what my ears were more calibrated to when I listened to these CD's. As I raised the volume loud, but not near distortion, the fuses went. That was it for the Krell for the time being. I went as far as unplugging it.

I should have switched amps with different speakers at that time, but went on a road trip for replacement fuses that took a while. I got some 1/2 amp ones as well as 1 amp. I wanted to see if the fuse was the issue. I hooked up the Hafler to the monitor 5's. I think the bass sounded a little better than the Krell, but too much time had passed for me to be sure. I have to admit there was less bass than I remember. Newer CD's sounded fine, and both old and new never blew the 1/2 amp fuse.

I hooked the Krell back up the next day and it ran fine, and sounded fine, although it has me a little spooked. The only real difference is at the time the fuses blew, I was using the preamp on the Krell. The CD also had a lower output level than today's CDs. Maybe something went funky with the preamp stage for a while.

Remembering far back, I think I replaced the 1 amp fuses with 1/2 amp because I had them on hand at the time, and figured they would be "safer" than the 1 amp. I don't remember exactly why the fuses had blown the first time. Either the record player had an issue or got bumped or I had flipped a switch or something while the volume was still high.

This got me thinking about fuses, polyswitches, or nothing. While I am more cautious and I hope smarter today, stuff can still happen. The general thought is polyswitches degrade the sound, but what about fuses? There are a few more connections, but do they add resistance or degrade the sound. Part of me says some type of protection is good, just in case.