The Roetest Tube Tester stands out as one of the most capable and thoughtfully engineered modern instruments available to anyone working with vacuum tubes. Designed by Helmut Weigl, it bridges the gap between classic tube‑era test gear and contemporary measurement practice: fully automated, PC‑connected, and able to characterize tubes with a level of precision that vintage testers could only approximate. Where traditional emission or mutual‑conductance testers offer a quick “good/bad” verdict, the Roetest delivers full operating‑point analysis, dynamic curves, matched‑pair data, and detailed parameter reporting—essentially giving you a compact laboratory tailored for thermionic devices.

For restorers, audio builders, and collectors, it provides something even more valuable: repeatable, trustworthy measurements. The system applies real operating voltages, logs results digitally, and produces plots that make tube behavior immediately visible. Whether you’re validating NOS stock, diagnosing a misbehaving amplifier, or documenting a restoration project, the Roetest turns tube testing from a chore into a disciplined, data‑driven workflow.

I built my Roetest V10 several years ago (early 2023). Since then I have added many different tube socket boxes in order to test various types of tubes which are new to me.

Constructing a socket box is time consuming and somewhat tedious. Starting with a standard size project box (appropriate for the socket) there is layout, marking, cutting, drilling, fitting and (finally) wiring for each and every new socket required.

It occurred to me that I could use 3D printing to accomplish the first four steps (layout, marking, cutting and drilling) in a single operation. Other advantages of 3D printed socket boxes are:

• Better accuracy of holes and openings
• Repeatable layout of holes and openings
• Reusable templates
• Choice of materials
• Choice of colors
• Flexible layouts
• Customized boxes

I chose to use OpenSCAD as I had some experience with it, and it has readily available projects which can easily be adapted to to Roetest socket boxes. OpenSCAD is available to use free of charge.

After a couple of iterations, I was able to produce a basic socket box which is easily adaptable to any tube socket I may need. I chose to print the box itself in PETG for mechanical strength and temperature resistance. The base plate was printed from PLA+ material.

90% of the holes and and openings (baseplate, socket, connectors) are ready to assemble without any additional cutting or drilling. The only manual operations I did were to countersink the baseplate holes for the countersunk bolts and trim off the support on the plug socket opening. This particular socket box is for the Septar B7A tube socket. In addition to the socket, I put in two flat-edged holes for banana jacks to accommodate an external filament supply. For tubes that require large filament currents, it is good practice to use an external filament supply. For example the 4D32 requires 3.75 A (nominal) at 6.3 volts. Although the Roetest can provide up to 15v at up to 5A continuous output for the heaters, I would rather use an external supply for high filament current tubes.

Here is an example of a completed socket for the GM70 triode:

I ran several extended tests (1 hour or more duration) with the GM70 (20V, 3A filament) and the socket box only became warm, about 35 ⁰C. When testing a tube where an external filament supply is needed, you simply set up the Roetest software to use external filament connections, and using a floating power supply.