The Bryston amps, as well as many other high end amps, DO NOTUsually a relay is required for DC protection, but it can be implemented by other means such as crowbar circuit (which is a means of shorting out the power supply of the amp if the DC circuit is triggered).
have DC output protection.
From the STEREOPHILE review:
https://www.stereophile.com/solidpoweramps/108bry/index.html
Because the 28B-SST's components and circuits are rugged, the protection-circuit parameters are not as restrictive as are found in other amplifiers. Even so, the protection circuit is designed to handle most fault conditions, including shorts and DC offset.It would not surprise me to find out that the above comment is actually false; that would not be a first for Stereophile. Calls to Bryston here in the US and Canada did not get me to the bottom of it. I'll try again on Monday.