The power limiter has more applicability to 4 ohm loads. There is no 4 ohm 8 ohm switching on this amp.
And the currents needed to light up the power limiters won't be available at 8 ohms. No matter where you have the settings dialed in.
150 watts into 8 ohms is 34.64v. 180 watts max into a 4 ohm load is 26.83 volts yet the amp can try to deliver 34 volts into 4 ohms.
but
if you inadvertently have less than 8 ohms:
That same 34v pushing into 4 ohms is 289 watts
the power supply isn't up to it, but it will put enough current through the outputs to probably overheat them.
The power limiter senses the excessive current through the outputs via the emitter resistors. It won't be bothered by 8 ohm loads.
i would set them.
If you don't think you have the dummy loads - normally both load resistors are used at the same time - 1 to a channel
BUT
the power limiters are adjusted one channel at a time, other channel unloaded
SO
two 8 ohm loads in parallel IS 4 ohms...
some math doodling, not to be lost on some scrap paper blowing around here:
200 watts is 28.29 volts.into 4 ohms. that would be 7.07 amps through the outputs, 3.5 amps per pair. 1.75 volts across a 0.5 ohm emitter resistor
150 watts is 34.64 volts into 8 ohms. that would be 4.3 amps through the outputs, 2.165 amps per pair. 1.08 volts across a 0.5 ohm emitter resistor
The only thing I don't know for sure is what voltage gets Q13 & Q14 working.
