Tube testers
Click on the picture to get a larger view
For those interested in more information I strongly recommend Alan Douglas book
Tube Testers and Classic Electronic Test Gear

avo-mark4.jpg (49692 bytes)
The AVO-Valve Characteristic Meter was one of the most used tube tester in Europe. The picture shows model Mark IV. All the sockets on the top of the unit are connected in parallel and with the use of ten thumbwheel switches the pins are connected to the test points for filament/heater, cathode, control grid, screen grid, anode etc.

tubetest-eltron.jpg (51153 bytes)
This is an old Swedish tube tester made by Eltron.

sv-tubetest.jpg (68895 bytes)
Another Swedish Tube Tester

tek570.jpg (70103 bytes)
Tektronix Type 570 Vacuum-Tube Characteristic-Curve Tracer. The 570 was provided with a set of various tube sockets which was to be installed and jumpered to the appropriate test points. Tubes can be checked for gain and matched if desired. The instrument in the upper right corner is for adjusting the screen grid voltage.

sofia.jpg (28395 bytes)
This was a unit that you connected to your computer and get all parameters tested easily. It was made by Audiomatica in Italy but is no longer in production.