My first tube project was building a phone preamp with 3 times ECC83. Next will be a complete tube audio amplifier using no semiconductors at all. But how to select the best tubes from the junk box? After some experiments with a Heathkit TC2 and the US tube tester I177B I got more interested in testing radio tubes. For me it is old school technology. I was grown up with semiconductors and processors. I've a nice collection of tubes but selecting or matching with a go/ no-go tester is not really what I was looking for. Via the web I found the uTracer website.
uTracer home
uTracer order
Really beautiful!! A great design, so I ordered a kit. Many thanks to Ronald for the technical work and Marie-Jose for the logistic support. Delivery was very fast and the kit was very well packed.
In the junk box I've found a nice case. But it is not very big so a real challenge to have all components fitted. Especially the height was a challenge. I had to do some mechanical work. Because additional to the uTracer printed circuit board there is an old laptop power supply, two step down converters (one for the 1.5Vdc battery voltage, the other one supplying 5Vdc), the small home brewed USB/RS232/BT interface and not to forget all the wiring. The 5V is used for the small home brewed interface. Now it is very easy to connect a PC to the uTracer, it can be RS232, USB or Bluetooth without any switching. I used some old TTL ic's to make the combiner for the interfacing. Just connect and select the right COM port in the software. On the rear there is a male 9 pin outbreak connector to connect small cases with less common used tube sockets. On the tester itself I selected the Rimlock (B8A), Loctal (B8G), P-socket (P8A), Noval (B9A), Miniature (B7G) and Magnoval (B9D) socket. I use small plastified cards for the connection diagram. Quite simple. The construction manual is very well documented. The uTracer worked at once. Started testing with EL84 tubes: one tube had only 8mA Ia with 300Va, 250Vs, -0Vg. Other EL84 tubes had an Ia of more than 100mA. So it is very interesting to play with this beautiful tester. Most ECC tubes in my junk box have identical curves for both triodes, but I found also some with (great) difference. Kind regards, Eric