On Friday, December 18, 2015 at 7:37:37 AM UTC-5, Mark Zacharias wrote:

Prefer direct-coupled amps (with a competent protection circuit!)
Mark Z.

Funny how certain things trigger a memory of something forgotten for years. I had a Hitachi brand receiver that the customer said blew out several speakers on one side. I checked the outputs, nothing shorted so I hooked up some cheap TV speakers at low volume and there was no DC to speak of on either side and it was clean and clear. I let it run a couple of hours and suddenly there was a loud hum, pop, and one TV speaker that puked it's voice coil. This was direct coupled amp with no type of speaker protection. Ended up junking it.