Sundown Audio Salt 6K

I have two Salt 6 amps on two 18" nsv4 subs with both subs sharing a common chamber. Each amp is wired to one sub at 1 ohm, starting load. Plenty of reserve lithium battery power and alternator amperage with minor voltage drop under burp conditions. I am having some issue that's concerning regarding one of the two amps. Both amps are gain matched around 86-87 volts AC and scoped. Both amps begin to clip around 86 volts AC unloaded when I initially set up gains.



With one particular amp, when it reaches clipping under load, the voltage drops dramatically about -20 volts and the sun immediately acts abnormally as it unloading or over ekxcurting, as I’d describe it. The other Salt 6 also begins to flip, as expected under the same condition, but it still drivers normal, per say, and it’s respected subwoofer doesn’t display the same issue. This issue is not specific to one sub, leading to the conclusion it’s not unloading or an individual subwoofer problem. You can swap subs to the troublesome amp, and the new amp acts in the same way. Thus duplicating the problem. There is also an audible noise then this happens.