after my last "adventure" (https://www.amb.org/forum/enclosure-for-beta24-t3573-60.html) I'm concerned about the safety of my β24 build, which basically follows the reference build. I'm sure, this thoughts are not new, but I think it's worth while talking about it.
Things I'd like to avoid are (in order of severity): fire, speaker damage, severe amp damage. My current build is not immune against any of these mishaps.
1) Main fuse. I use 6.3A slow one. A 4A one blows on power on because of the high transformer inrush current. But even a 4A fuse would probably withstand a secondary short, so in case of a problem with rectifiers, or OPS failure (MOSFETS short), we will have a nice firework, and it will probably continue until the transformer overheats and we have a primary short. The fire fighters will probably have arrived at this time...
I guess, a 3-3.5A fuse (at 230 V) would bring some safety, but then we definitely need a soft start circuit.
2) Power rail fuses. Ti's explanation, why he doesn't like them are easily comprehensible. Still in my opinion an overcurrent protection is desirable and necessary. A fast acting circuit on power rails, which could utilize a 10 mOhm resistor for current measurement, could switch the amp off and disconnect speakers in case of failure and thus limit the damage and nevertheless might have little to no influence on sound quality.
3) DC protection. No need to generally discuss it, especially in a DC coupled amp. There are a lot of circuits and kits available, but I haven't found a specialized solution for a balanced amp so far. One could use four "normal" boards instead, but it is not really elegant. The way to disconnect speakers (relay vs. "SSR" vs ?) is of course to be discussed...
4) Me and some other users have/had problems with the stability of Epsion24, and the 12V trigger circuit I use is more a workaround...
Provided that these 4 points are not absolute crap

Would like to hear the opinions of the specialists on this topic
