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Vacuum Tube Tester: The Roetest

Posted on March 17th, by Shaun Merrigan in Electronics, Tech, Test Equipment, Vacuum Tubes. Comments Off on Vacuum Tube Tester: The Roetest

I recently completed the construction of a PC controlled vacuum tester: The Roetest. This is a computer-controlled tube tester which works as follows:

  • Using the PC software, load the tube data from the extensive database
  • Verify the tube data and pinout on the screen; the tester configures the pin connections automatically
  • Run the tests for shorts and filament continuity
  • Run the required tests
  • Test the tube at full voltage and current (not a pulse test)
  • Save the result
  • Add the tube and test data to inventory
Roetest V10 Front Panel and case
Roetest V10 Main board and plug in boards
Roetest V10 Front Panel

Construction Details:

  • 4600 Solder Joints
  • 600+ Components
  • 20 separate circuit boards
  • Mechanical work for socket boxes + drilling and tapping heatsink
  • 150+ hours

Using the PC software, load the data for the TUT (Tube under Test). Pinout and base connection information is taken from an extensive database of over 22,000 tube types.

Roetest Load Tube Data Check Validity

The TUT is put into a “socket box” which then is slid into a mating connector on the Roetest:

Roetest Tube and Socket Box Connections
Roetest Tube and Socket Box Inserted

With the TUT inserted, we can check for shorts and open filaments automatically:

Roetest Filament and Shorts Test

Choose the type of test to be performed and execute it:

Roetest Choose Test Mode

Static (DC) Test Results for EL34 (JJ):

Roetest Screen Static Test Results

Curve Tracing for matching and evaluation:

Roetest Generate Tube Curves

When the tests are complete, all test results can be stored in the database, and an identifying label can be printed which will identify the tube in inventory.

Other functions available include:

  • Matching of tubes using curves
  • Identification of unmarked tubes
  • Full manual control of all tube voltages
  • Tube characteristics plotted over time
  • Rejuvenation/Regeneration protocols
  • Batch processing with automatic detection of inserted tube
  • Cold short test
  • Hot short test
  • Transconductance curve calculation
  • THD approximation
  • Fully automatic testing of double (triode/triode) tube systems
  • Full database management and query tools

I would describe the building process as requiring a large commitment of time, and meticulous attention to detail. I spent over 150 hours building and calibrating the Roetest, This amount of time is more than most people would take, but I wanted avoid problems caused by sloppy soldering or rushing through the assembly process. I was rewarded with my Roetest working correctly from the first power on.

Credit must go to Helmut Weigl who designed the Roetest and wrote the control and database software. He has been refining the Roetest with regular hardware and software updates for more than 12 years; I would classify it as a mature product that functions as intended: Roetest Website

Thanks for reading.

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