Need Help! My Class A Amp Is Running Very Hot

If it is so hot on the vents that you would get burned, I find it hard to believe, that Luxman would use a material such as plastic, as vents. 

Given what you have reported and Al's usual helpful stats it sounds like the amp is operating at normal temps for a Class A design. This is the main reason I am not a big fan of some of these designs--it's not so much the heat they produce and the impact on room temperatures. I have concerns about parts longevity in an enclosure that produces so much heat. Things get stressed at those temperature levels regardless of what specs they might cite and the repeated heating and cooling as you power up and down will also likely take their toll over time. I feel the same way about tube units that are not designed to allow the heat to dissipate easily from inside the cabinet. One of the reasons I love a ZOTL design like my LTA Ultralinear is that it runs remarkably cool for a tube unit. This will likely contribute to less parts failure down the road.

If you can hold your hand on it for 30 seconds, then it's not that hot.  Still, it's best to talk to the manufacturer/distributor if it really concerns you.

IF it is an used unit, make sure it is a 115v model ( not a 100v Japan model ) if you are in US otherwise a transformer is needed!

Read the paragraph under ’PROTECTION CIRCUIT’, on Page 1 of the Luxman AX590 manual: https://onahighernote.com/oahn/wp-content/uploads/2015/01/L590AX.pdf Luxman probably knows, how hot is too hot, for their product and have taken precautions.