25th of October 2021 Sergey reported his uTracer6 working!

Hi Ronald and Marie-José,

Thank you for your kit and the excellent manual. I already finished making and tested a pair of Soviet G-807 radio tubes. https://ua9uqb.livejournal.com/325300.html
There are plans to make a case, perform a full calibration and select pairs of lamps for my RIAA corrector and amplifier.


27th of September 2021 Have a look at Wayne’s great uTracer6!

It took several weeks to complete. Just wrapped it up this weekend and the uTracer6 is fully functional. Here is what I built.

Thanks for supplying a superb kit,


29th of August 2021 Antoon uses his uTracer as an extension of his AVO IV!

25th of August 2021 Dave is very pleased with his uTracer6 and used it to test a giant ELROG ER300B!

Hi Ronald, I can't thank you enough for the effort, years of experience, ingenuity and attention to detail that went into designing, productising the uTracer6 and turning into a kit.

The uTracer6 assembly instructions were again first class and I really enjoyed putting it together. Building it myself was part of the attraction.

As with my uTracer3 (which I'll still use for small tubes) I put the uTracer6 board into a simple plastic case with a clear lid so I can see the LEDs. Unlike the uTracer6 I haven't included any tube sockets. I'll build an external box for each tube-type with optimised anti-oscillation measures. You can see the 300B extension in the first picture.

The second picture shows a couple of Ihor Smal's ESP32-based units running his software. One of my original uTracer and one for my new uTracer6.

The only tubes that I currently have that can utilise the uTracer6's advanced capabilities are 6550s (and only just). I've attached pictures from both Ronald's software and Ihor's software.

I've ordered an XH-M403 DC to DC Digital Voltage Regulator Buck Converter for driving heaters beyond the capabilities of the uTracer6.

Thanks and regards, Dave.

25th of August 2021 Claes from Sweden reported his uTracer6 working!

Test setup with one vintage 6SN7, works now!
Made one mistake during calibration, cost one Mosfet in Anode HV ,T65. (hard to get).
Had a very god time during this trip. The instructions is great, Next is to box it.
Report later boxed.

Best Regards

Claes Jansson, Sweden

3rd of July 2021 Shin-ichi from Japan turned his uTracer6 into a beautiful instrument with a redesigned heater supply!

Dear Ronald

It takes almost four months, and now I have finished assembling my version of uTracer6 based tube tracer.
Attached tracing.jpg is its figure !

I made build-in dc filament supply ( heater is also available, of course ) to trace direct heating tubes easy. This circuit refers to the PWM1 signal of uTracer6 to generate dc voltage that tracks the value of the Vh field of the GUI. Soft start ( This is a nice feature ! ) and on/off operation are controlled in the GUI's manner. Missing PWM1 pulse during measure period doesn't affect on filament voltage. A collage from my notebook (block.jpg) shows the simplified block diagram of this supply. A tiny flowchart of square root calculation gave me an inspiration about this circuit. This simple algorithm revives from 70's, the Cambrian period of eight bit microprocessors.

Inside the cabinet with uTracer6 is shown in interior.jpg. The floating supply board is positioned under the uTracer6 board.

The mainframe of this tracer does not have tube socket. A socket of required type is set on the fixture box as fixture.jpg shows. Pin selection is done in the box. Two types of fixture unit I made. One for MT sockets and another one is for larger sockets of GT, ST, compactron etc.

I thank you and uTracer6 !
Happy tracing !!


29th of May 2021 Jonas traced the “heaviest” tube so far on the uTracer6 a huge GU-78B!

Hi Ronald and Marie-José,

I am very grateful to you for your adventure with uTracer6. 2021 May 29 The most powerful tube tested by uTracer6 is the GU-78B. The GU-78B is a Russian tetrode with a maximum anode dissipation of 2500W. The tube GU-78B requires forced air cooling, a fan is applied. Oscillations are suppressed and the tube shows a curve trace. In the attachment there are several pictures in the form of a report, for free use.

Best wishes


1st of May 2021 Gary reported his uTracer6 working!

The uTracer6 kit went together nicely, and as usual the manual was superb.
I can't wait to give it an appropriate case and put it to use!

1st of May 2021 Winfried sent me a few pictures of the monster GU-81 he traced with the uTracer6!

The GU-81 is a Russian military pentode with a maximum anode dissipation of 450W. The heater alone dissipates 120W (12V @ 10A). A look at the datasheet shows that the uTracer6 can only trace a small part of the curves! Winfried traced the GU-81 both in pentode as well as triode mode.

Winfried sent me a beautiful present in the form of a 3D printed case for the uTracer6 complete with all the accessories and in our national color: orange!

7th of April 2021 Francisco finished his uTracer6 and made a YouTube movie of it!


I have enjoyed so much building the new uTracer6 this weekend, and I gladly completed it without a problem. I have compared the results with my uTracer3 and they are exactly the same.

I attach some pictures and a short video.

Thank you again for this wonderful device.
Kind regards.

5th of April 2021 Windfried designed a beautiful case around his uTracer6!

Happy Easter Ronald,

I finished my uTracer 6 and be back with the pictures. I already finished two tube adapters also (next will be one for GU-81 tubes probably :-).

You can see the indirect LED signals at the neck of the tube adapter socket (starboard and port accordingly with red signalling high voltage and green for power on).

I found another thing in the manual that could be corrected. At page 57 you recommend the use of a 330µH inductor wich is already included with the pcb/kit.

Best Regards,


22nd of March 2021 Marcello from Itally finished his uTracer6 and immediately tested a massive WE 300B!

Dear Ronald and Marie Josè,

This morning I finished the uTracer 6, following the construction manual to the letter.
I did perform the calibration correctly, extending the calibration points to 600V, and all worked flawless.
Now I'm playing with some tubes, to familiarize myself with the instrument before closing in a proper case (external PSU yes/no... I think it will be necessary).
In any case, I want to thank you for designing and sharing this useful tool, essential to playing consciously with our beloved tubes.

All the best (from Italy)


28th of February 2021 Shi-ichi from Japan reported his uTracer6 working, and his wife made a great compliment about the esthetics of the PCB!

Dear Ronald & Marie-José

Thank you for your mail.
I attach two photos with this mail, the uTracer6 PCB I constructed and tracing scene. Please use them freely.

Add to my last mail, three modifications are applied to PCB.
LA1 through LA4 RFI suppression beads are covered by insulating sleeve and they are mounted on paper phenol resin sheet.
To avoid careless touching is the reason. They are tall.
Values of parts in the grid bias trimming circuit are changed.
R45 2M7 to 390k
P40 100ohm to 500ohm
The adjustment range was slightly narrow for my PCB condition.
Probably 200 ohm trimmer and 1M ohm R45 is better. But I don't have 200 ohm trimmer in my parts box.
POWER led is changed to green one. Simply because I usually use GaP green led for power indicator.

At this time, tracing is done on a lunch tray. This style is comfortable for experiment.
Upper left unit is USB to serial converter with command display. This unit includes TX/RX isolator by means of two photo couplers, to eliminate large ground loop.
A 6J11 dual pentode compactron is the DUT.
Measured plot image is collaged on the tray.
I am very satisfied with this result. Thank you Ronald!
When I understand enough about operation of this nice device, I will start designing the enclosure for uTracer6.

Yesterday, I showed uTracer6 PCB to my wife.
She said to me, "Mr.Dekker has his own aesthetics, I can feel it. This board is beautiful".
She is a graphics designer. I wish my modifications do not spoil your board design.


20th of February 2021 Roger Whigham finished his beautiful uTracer within a few days, encased and all!

Hello Marie-José,

The kit went together very well. The instructions were clear and easy to follow. You and Ronald have done a great job putting this together. I really appreciate your effort.

I've attached some photos of the finished product. In case you're wondering, I built the chassis before I received the circuit kit. Although I've only tested a couple of 12AX7's, I haven't seen any oscillations yet. I'm keeping the snubber handy in case it is needed.

Thanks again for all your hard work.

Best regards,

19th of February 2021 Freddy from Germany is the first of the non-beta testers to report his uTracer6 working!

Hi Utracer v6 arrived today, I have assembled and calibrated, works great. I have tested RF Zero Bias Transmitting Triodes, Eimac 3-500Z Russian G811, American 811A , Cetron 572B , Svetlana 572B, and Chinese 572B up to 1 KV Anode and +120V Grid1 via screen Booster.

All measurements are equal to microtracer v3 biz only up to 400 volts and 600 mA current after modification. The next day I will test some audio tubes el 34 el 84 6l6 6p3s kt66 and some double triodes ecc 83 85 88 and Russian equivalent 6n1p 6n2p and 6p3s.

Thank you and have a nice day