Just saw these while perusing the audio amps at Newark, and was like "what" that can't be right. So I bought some, and then thought I must have a look at diyaudio for any possible build ups or discussions, not much. I've got fond memories of the stk-0080's (sanyo), should be fun. Cheers
I didn't realize these were still popular. Used to see them fail rather spectacularly (and with some frequency) in the shop where I worked back in the day. Maybe some were better than others?
Fun story: Sometime back in the '80s or so, guy brings in a medium-level Sony receiver, complaining that it had cooked both of his woofers. Soon discovered that the left channel STK had failed to the positive rail, and the right one was sitting on the negative, +/- 35-40 volts or so. Here's the catch: There was only one DC protection circuit, shared between both channels, fed by a resistor from each. Since one output was at +35 and the other at -35, the sum at the resistor junction was - you guessed it - zero volts. No problem! The speaker relays clicked on, and... What's that smell?
We couldn't believe they were too cheap to include another 5 cents' worth of parts to duplicate the protect circuit properly. Hell, all they really needed to do was make those 2 resistors different values!