Tube amp location

Look into the "silencer" 12 volt computer fan. This is one of the lowest noise computer fan. You can also hook up an adjustable "wall wart" and adjust the voltage accordingly. I even put a lamp switch between the wall wart and the fan to turn my fan on/off. You probably need 2 of these fans to cool your amp.

If the tube amp operates in Class A, you are going to have to move a lot of air. The on top of speaker scenario is going to be a problem with microphonics and feedback. If you have to go tubes and cannot use monoblocks on floor behind speaker, then you should go with a Class A/B amp known for running cool(er), and with fewer tubes overall.

My last solution with your wife exceptance problem, why not just buy another entertainment center. I would look for a larger unit with more room inside for your gear. Something that you both find attractive be it wood,metal,marble, and granite or any other material's or a combo that would go with your decor. Look for a unit with good ventalation and solidly built.

Many posters seem concerned about the transmission of vibration from the speaker cabinet to the amplifier if the amp is placed on top of the speaker. IMO this concern is misplaced and over stated. The speakers are not flimsy. The Cornwalls are constructed of heavy plywood with a veneer layer. They are more than sturdy enough to support all but the most massive monoblocs. Tube guitar amplifiers are typically built to be positioned right on top of the speaker cabinet(s). The sound volumes from the guitar amps go much louder than home speakers, yet there is little regard given to vibration transmission. It doesn't appear to effect the sound, nor does it impact reliability. Are people forgetting that tubes are very rugged (that's why the Russians used them in their military jets). If you place the amps on an MDF board (or other material) and then isolate the board from the speaker with cork, sorbothane, etc. then you will have solved the "vibration issue". Is it as good of a solution as getting dedicated Gran Prix amp stands? No, but it's simpler and more cost effective than placing the amp in an airflow limited cabinet.

BTW, tube damper are a good idea whether you place the amp on top, inside, next to or even underneath the loudspeaker. They can do a good job at lessening thru air sound transmission artifacts.

My wife was not too sure about my pair of McIntosh 2102 amps, either. Then she noticed this is where the guys all gather as they just stare into the blue lights while I explain my system.

I waited a while before pointing out that this is where the guys can finally go while she and her friends hang out in the kitchen.

Amps can be really beautiful. How about getting her that piece of furniture she has been wanting...?