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Tube Curve Tracer for Sale

Based on the uTracer3+ kit. I built several of these for a project that is not going into production. These were intended for use at the factory for testing and sorting of various tubes.

Since I don’t need more than one curve tracer in my life, I have 3 of these for sale.

About the curve tracer:

  • Based on Roland Dekker’s uTracer3+ board. There is a lot of info about this board at www.dos4ever.com/uTracer3/uTracer3_page0.html. This is a very nicely designed kit that implements a full-featured curve tracer.
  • The finished unit has a rugged USB connector, AC mains IEC connector and switch, internal power supply (19V laptop supply), USB to RS-232 adapter (Prolific chip set), front panel status LEDs, and keyed banana jack connections. The processor has been replaced with a Black Magic Amps version that adds a huge number of improvements (see below). Everything is packaged in a Pelican-type case made by Seahorse, with a professionally made front panel, as shown in the pics.
  • Since this was intended for factory floor use, I designed plug-in adapters that mate with the banana jacks on the unit. Each adapter is wired for a specific tube type, so there is no chance of setting switches or jumpers incorrectly. I include one adapter pre-wired for the 12A*7 family of dual triodes, along with another 9-pin adapter and two 8-pin Octal adapters. These adapters are not wired internally yet. You can configure these for your favourite tubes using short jumper wires.
  • Since some users will also want to test various other tubes, I designed a “universal” adapter, one of which is included. This has 9-pin, octal, and 4-pin (see note below) sockets that will support testing of a wide range of tubes. Use short banana jumper cables (not included) to connect to the main unit.
  • The adapters are housed in 3D printed cases. I can provide STL files for these if you want to print your own. I can also provide Gerber files for the adapter boards if you want to make more (for your own use, please.)
  • A few specs:
* Anode and Screen voltage: 400V Max @ 200ma
* Grid voltage: 0 to -50V
* Heater: 0 to 19V @ 1.5A
* Approximate size: 11in x 10in x 5in
  • The Black Magic Amps (https://bmamps.com/v01/home/techie-corner/utracer-utmax/) processor supports better anode, grid, and heater voltage setting accuracy, firmware updates over USB (unit is shipped with the latest version, 3.06), much faster tests, and overall more stable operation. The original processor is included if you want to switch back for any reason.
  • The unit comes pre-calibrated and ready to go.
  • Note that the grid voltage is -50V max. While the universal adapter has a socket that will work with tubes such as the 300B, this may not be enough grid voltage for your particular tests. In that case, there is a mod you can make to the uTracer board to increase the grid range to -100V. There is information on both the dos4ever and bmamps sites on how to do this.
  • Other mods: I’ve made a mod to the grid supply circuit to improve performance at low voltages. Unmodified uTracer3+ boards have trouble with grid voltages below about 0.5V, but with this mod they work fine to below 0.1V. I have not made any other mods to these units.
  • Other mods you can do: as mentioned, there is a -100V grid voltage mod. There are also a wide range of mods that are documented on both the dos4ever and bmamps sites, including ones that provide faster testing times, higher anode currents, a grid offset mod that allows accurate grid voltage down to 0V, and more.
  • Software: the dos4ever site has a Windows application that works well and has many useful features. You can download it for free from the Downloads menu at https://www.dos4ever.com/uTracer3/uTracer3_pag0.html. The bmamps site has an excellent application that runs on Windows and Linux, and has many improvements, including faster testing, easier calibration, a very nice GUI with interactive graphs, spice model output based on measured data, and so on. You can download it for free from https://bmamps.com/v01/home/techie-corner/utracer-utmax/. As a bonus, this app is also open source, so you can add features of your own.
  • NOTE: I am in no way affiliated with Ronald Dekker, Dos4Ever.com, Black Magic Amps, or Nick Barton (owner of BMAmps). I have simply used their products to make these curve tracers. Hats off to both Ronald and Nick for the excellent work they’ve done and put out there for us all to use.

Included with each Curve Tracer:

1 assembled, tested, and calibrated curve tracer in Seahorse case
1 pre-wired 12A_7 adapter
1 unwired 9-pin adapter
2 unwired octal adapters
1 assembled “Universal” adapter for 9-pin, octal, and 4-pin (300B type) tubes

USB cable and AC power cable not included.

Cost: $1500 USD, plus shipping from Australia