Adcom Amplifier Speaker Protection

Power amplifiers often (usually?) fail with a shorted output device that causes DC output at the positive or negative rail voltages.

Adcom amplifiers have fuses on those rails (some with them in holders on the back panel) which will probably blow before something bad happens unless you're running an active multi-amplification setup.

Although you'd probably exceed the woofer's power rating (ex: the 200W rating on the 555ii implies 40VRMS and 56V peak. It has 7A fuses; so it'd deliver 392W until the fuse blew) the fuses take much less heat to go which seems to leave driver voice coils intact.

The small tweeter voice coil in a multi-amplified setup without a DC blocking capacitor might not fare so well, although many dome tweeters used in expensive speakers aren't that expensive and where they are replacement voice coil + dome assemblies are available.

DC protection circuitry can be added to an amp that lacks that feature, as long as there is room in the chassis. There's quite a bit of discussion on the topic at diyAudio forum. I've done such retrofitting. While catastrophic failures are rare, who wants the full rail voltage dumped into a pair of speakers with expensive or unobtainium replacement drivers ?

Some speaker makers do have some form of protection built in but most seem to rely on the amp maker to shut down the outputs if there is a massive fault in the amp.

Not countless speakers as Adcoms in general are reliable amps. Also when an amp fails it does not always do so in a way that would take the speakers with it but in those few times that it does its adding injury to insult. You could give yourself some level of protection by putting fuses on one leg of the speaker wires. It is easy enough to figure out the fuse value. There are many who would argue that it will effect sound quality by doing so but then there are well respected amps in the market that have fuses or relays inline to the speakers for protection.