The Story
The µTracer Kit is an excellent tube curve tracer, because it measures with pulses
and not the old fashion way to kill the tubes with too high continous
voltage/current. With the PC software you can calibrate the hard ware
save/print out the curves.
Also it’s possible to get the curves as numeric files to create with supplementary
software tube models for LTspice. This tube models are out of the tube
you are holding in your hand and not created out of “very nice painted” curves
from the tube manufacturers.

   
I add also an additional fillament power supply, made out of one more PC power supply,
adjustable step down regulator and digital voltmeter.