Here is the computerized Amplitrex AT1000 Tube tester.
This tester will test the tubes at HIGH VOLTAGE. Most tube
testers don't have this capability. So when your amp gets
shipped the tubes have been tested and matched under the
same high voltage load the amplifier is going to be running
the tubes at.
You can purchase an amplitrex from Chris Terraneau
sales@autobias.com. Chris is an outstanding electrical
engineer with a love for tubes. Go to his site
http://autobias.com/