I'm going to buy a new shelf unit for my audio set and I'm not sure that
this one will ensure proper cooling conditions for my amplifier.
The max spacing between the top of the ampifier and the shelf above will be
about 1,5 cm (0,6"). The rear and both sides of the shelf unit are open so
the amplifier will have a lot of space around itself. The amplifier's power
is 6x75W RMS and the nominal power is 290W.

Will these conditions be good enough to ensure proper air circulation and
cooling of my amplifier?

Rgrds,
Wojtas