Here is a link to a short video “courtesy of Brent Jessee Recordings” Brent does a fine job of testing and grading the tubes he sells. (I have purchased tubes over the years from Brent and have recommended others to him) The video link will give you an idea of what I’m launching here at Classic Tube Audio with my “Tubeology” testing and grading process. (This will not be a process in competition with Brent) it is a service that I offer with my restoration/repair work or to customers who send me tubes they have that an in-depth test process can be performed. I will however offer on occasion “Tubeology” tested tubes for sale. But it is not my goal to compete with any of the fine offers by Brent or other tube sales operations
I’m just going much more in-depth. I have a highly modified Tektronix 576 scope, adding to this several precision regulated outboard power supplies, a precision “stepper amplifier” that allows for a huge range of bias voltage’s to be applied x10 or -5 volts =-50 volts giving me a bias range from 0 to -500 vdc. I’m also adding a unique way to actually load the tube and apply a/c signals (frequency sweeps). My goal is to provide a level of test results at a “lab level” many other parameters of the tubes will be supplied in my measurement results. At this time these results are proprietary to the “Tubeology” process.. More to come soon. The “Tubeology” process is a huge undertaking so of course I’m delayed in the roll-out. But it’s going to be worth it!
In the mean time enjoy Brent’s video.