Component Stacking Question

You might get away with it by using a platform and footers between the pre and amp with emi + rfi rejection.

What mijostyn said!

tough to get a better amp for the money and even better when parts are upgraded. Great little sleeper amps.
And yes, don’t stack them. Best to get a cheap shelf set. stable, cheap, etc.

Preamp might be decent too, have never seen a image of the guts of them. One model of preamp, from that series and company (inkel).. was good enough to the the base unit for the Adcom Gfp-1. Also sold under the sears brand, LXI.

these are both Korean inkel products. styled differently, in minor ways... and the amp is slightly modified.
http://audiopub.co.kr/wp-content/uploads/2018/01/T_adcom-gfp1.jpg

Temp is OK.

Weight, maybe. Is the preamp strong enough for the weight?

Noise - Power transformers can radiate a lot of EMF noise, which can be picked up by other equipment too close to it. You'll hear it as hum.