Need Help! My Class A Amp Is Running Very Hot

Contact the dealer or manufacturer directly and explain the situation.

This is not normal.  Don't take any chances.

Doesn't matter what the problem is, and there is a problem.  If you aren't prepared to fix it your self, then an authorized service center or the manufacturer is the way to go.

It appears to me that the bias is way off. However, a simple solution (not the best) is to adjust the bias back to where it should be.  However, what caused the bias to float way off in the first place.  This is not normal.

enjoy

How hot is too hot, how hot is burning hot?

Measure with a thermometer !

You probably shouldn't have it placed inside of a poorly ventilated cabinet. My Class A amp is warm but not burning hot to the touch but I choose place it on an amp stand, not even within a rack.  Ventilation is important.

The L-590AX is spec’d as consuming 220 watts at idle (310 watts max). The L-590AXII is spec’d as consuming 260 watts at idle (330 watts max). Both models weigh about 63 pounds. The amp’s heatsinks are entirely enclosed within its metal cabinet, and are immediately adjacent to the side-panels, as can be seen here:

http://www.luxman.com/asset/product/L-590AXII/gb4.jpg

So the escape route for the heat corresponding to those power consumption numbers is almost entirely via the vents on the top, supplemented to a small extent by radiation through the side panels.

Given all of that it seems to me to be very possible that what you have described is normal, but it’s hard to say for sure. Perhaps another owner of one of these models will chime in.

@three_easy_payments, I believe the OP’s reference to "cabinet" pertained to the metal enclosure of the amp itself.

Regards,
-- Al