How to physically move large heavy 100lb amplifiers easily (up and downstairs)

Hah, I watched those videos imhififan.  There was another video that came up just after it:

https://www.youtube.com/watch?v=wUbm1e1PdwI

The Northern tool 3-wheel type can help climb stairs, but it appears that it's harder to turn/rotate this type of hand truck.  A hand truck with big tires and sliders appears to work better overall.  An example:

https://www.amazon.com/Tyke-Supply-Aluminum-Climber-Handle/dp/B01ATY2HI4

Class D lol

2 kids + $20 = job done

https://www.amazon.com/BestEquip-Capacity-Climbing-Three-Wheel-Portable/dp/B06X157K4T/ref=sxin_9?asc...

Used this to move 200lb+ Wilsons and Egglestonworks up 3 flights of stairs (27 steps). You’d still need 2 people (one to pull, one to make sure it wouldn’t go backward) and some ties.

The base of this cart is pretty wide.

IMHO way better than hiring 2 kids + $20 and have their backs injured, and/or drop your stuff.

You never said how many stairs. If a straight shot (as we used to say in Chicago), You could buy 2-3 sheets of 3/8 plywood and lay them on the stairs (connected with "menders"). Just tie some cloths line around the box and sprinkle some talc on the chute to lessen friction. Just drag the sucker up the stairs (amp in box of course, two people better than one).