Do not change the orientation of the VT-100s... They should sit on their feet... You really do not want to have all of the heat rising to the circuit card that is on the top. One of the things that will happen is shortened tube life. With that in mind - the biggest "no-no" of this all is having 1/2 of the tubes in this amp operating base up.. Just a bad thing to do to tubes.. A quick consultation with the owner's manual will also confirm ARC's position on how the amp should be orientated.
Per Sean's post, the best way to run tubes is base down. Audio Research has made the choice to run the tubes horizontal, which is why the later units have fans to assist in the convection process and reduce issues with horizontal tubes.
The next problem you will have is that the amps are not on their feet. ARC has done a decent job of providing feet that actually do some good in terms of vibration isolation. You will find this out of you ever experiment with isolation tweeks and the VT-100..
Per Sean's post, the best way to run tubes is base down. Audio Research has made the choice to run the tubes horizontal, which is why the later units have fans to assist in the convection process and reduce issues with horizontal tubes.
The next problem you will have is that the amps are not on their feet. ARC has done a decent job of providing feet that actually do some good in terms of vibration isolation. You will find this out of you ever experiment with isolation tweeks and the VT-100..