Vacuum Tube Curve Tracer (The FUtracer)

[KungFuJosh]

I got a laser engraver to play around with.

The cover idea looks pretty cool:

[KungFuJosh]

I retro-engraved the two testers I still have, it came out pretty darn good (though the logo is inconsistent for some reason):




Looks cool anyway. I'll maybe try a vector logo instead, or burn it vertically instead of horizontally and see what happens.

Thanks,
Josh

[KungFuJosh]

We're pretty close on releasing new firmware and software versions. Some cool features include a Calibration Wizard for much easier calibration (not that it was that difficult anyway lol), and storing calibration data on the firmware chip.

For those that already have an FUtracer, you can send me your chips to update the firmware free, or I can sell a discounted chip instead. That's up to you.

I'm also considering making a new socket board version to also including another tube type or two. One I'm thinking about is the 7 pin 6028. Any other desired tubes not yet covered?

Thanks,
Josh

[KungFuJosh]

We've been going a little crazy with improvements, and we're testing what's hopefully the final version of the firmware/software for this release.

We've added a grid mod that gives much higher accuracy under 200mV. I ran a sweep from 0 to -1 Vg with 10 steps, and this was the results:
-002.0mV
-100.3mV
-199.6mV
-298.2mV
-396.5mV
-495.1mV
-593.5mV
-692.1mV
-803.0mV
-901.7mV
-1.002mV

That's pretty darn good.

I made a video clip showing tracing live in full screen with the latest version of the FUtracer software: https://youtu.be/dle7xnOKeK4

Thanks,
Josh

[KungFuJosh]

I think we're finally almost done with the new firmware/software versions. Tracing is twice as fast now! Check it out:

Thanks,
Josh

[KungFuJosh]

The new versions are finally done. We've added some cool features/and general improvements. The latest version of the GUI is live on the futracer.com website.

New kits will ship with the latest firmware (currently version 2.07). For anybody that already has a kit, you can send in your chip to be upgraded for free, or you can purchase a new programmed chip for $30 including shipping within the US.

Email support at futracer.com to inquire.

Thanks,
Josh

[KungFuJosh]

Here's an update for anybody interested:

There's a mod for the version 6.9 PCBs on the futracer.com site for better low grid voltage accuracy between 0 and -1V.

I've recently ordered v7.0 PCBs that include the higher grid voltage accuracy. This set is 2mm thick, ENIG surface finish, 2u” gold thickness, 2oz outer copper weight, and include the USB chip and socket, PGAs, and anti-static SMT stuff already done.

Once I receive them, I will build 1 or 2 units to test them out, and then I'll have some PCB kits available for sale (price TBD), along with an updated build instruction set for this version.

Thanks,
Josh

[KungFuJosh]

I got the new FUtracer v7 boards in, with the PCBA service done...and they're awesome! They did a great job with those tiny little bastard SMT chips.

I built it, calibrated it, and tested it, and it's all good. I'm waiting on a couple tube sockets then I can test the new socket board version that also includes 408A (7pin) and similar tubes.

Once that's all tested, I'll put together some kits for anybody interested.

Thanks,
Josh

[KungFuJosh]

My missing sockets are on the way, but I felt like doing a test anyway. Looks pretty darn good for an old 6P14P tested without an enclosure.

The test setup (powered by a bench PSU):


A quick set of curve traces:


Thanks,
Josh

[KungFuJosh]

The new version 7.0 FUtracer kits are fully tested and ready to go.

This set is 2mm thick, ENIG surface finish, 2u” gold thickness, 2oz outer copper weight, and include the USB chip and socket, PGAs, and anti-static SMT stuff already done. The price for the new kit with the Main PCB, Socket Board PCB, PSU connector PCB, and programmed/user updateable Firmware Chip will be $200. Shipping outside the US is extra, but within the US is included for now.

The new socket board version is mostly SMT. If you want a kit with the SMT work on the socket board done, I will supply the parts and do the SMT work for an extra $50. The pads are all hand-soldering sized, so don't be too scared if you want to do it yourself. 

This is the set:



You can contact 'support at futracer dot com' for more info or to purchase a kit.

More information including build and use guides is available at futracer.com.

Here was the final test setup:


Thanks,
Josh

[b_force]

I am also popping in just to stay updated!

Funny enough I had a similar idea, probably for VERY similar reasons to develop my own tracer.
I am actually very curious what you did for the HV boost converter, because that one most definitely needs attention from "the other guy".
Otherwise just send me a PM, because I can share a design I am working on (for another project)..

Personally I would do things differently, just to try to cut down in cost (not quality), but that is also a matter of taste and preferences.

The reason the project went on the (Far) back burner for me, is that personally the SPICE models that can be found seem to be adequate enough to design circuits around them.

One little thing of feedback, the engraved numbers on the chassis now say "ECC83, EF800, EF86, EL83, EL34", but that seems to be rather confusing?
Assuming that it's possible to also be able to trace other tubes as well.
So I personally would stick to a more generic name instead.

Also, I assume that the last picture above my post is a prototype?
Because the wiring can need some attention.

What's the reason to go for ENIG finish as well as extra thick copper btw?

[KungFuJosh]

I am also popping in just to stay updated!

Funny enough I had a similar idea, probably for VERY similar reasons to develop my own tracer.
I am actually very curious what you did for the HV boost converter, because that one most definitely needs attention from "the other guy".
Otherwise just send me a PM, because I can share a design I am working on (for another project)..

Personally I would do things differently, just to try to cut down in cost (not quality), but that is also a matter of taste and preferences.

The reason the project went on the (Far) back burner for me, is that personally the SPICE models that can be found seem to be adequate enough to design circuits around them.

lol, I'm not surprised. Let's just say we're not the only ones. At least for now, this is the final version of the project. In the future I may wish to do a higher voltage / current version, but it's not a priority for my tube uses. I test partly for design, but more often for quality and targeted values for a given circuit.

One little thing of feedback, the engraved numbers on the chassis now say "ECC83, EF800, EF86, EL83, EL34", but that seems to be rather confusing?
Assuming that it's possible to also be able to trace other tubes as well.
So I personally would stick to a more generic name instead.

That chassis was marked for me, but you're correct, any common pinouts will work with their respective sockets. I used those tubes rather than listing all the common tubes that work, since most are pretty straight forward. If you have a simple naming scheme that isn't confusing, I'm all ears. I actually do have a custom chassis being made for the new set, so I'd love to get some ideas on better labeling. I didn't want to do 12AX?, that looks weird to me.

Also, I assume that the last picture above my post is a prototype?
Because the wiring can need some attention.

The picture above your post was my setup for testing the boards. It's not a prototype, but it's not the intended setup either. It should be properly setup in an enclosure.

What's the reason to go for ENIG finish as well as extra thick copper btw?

Better quality, and the best options / for ROHS compliance.

Thanks,
Josh

[b_force]

Better quality, and the best option for ROHS compliance.

Thanks,
Josh

I don't follow the "best option for ROHS compliance" ?

The finish is either ROHS compliant or not.

[KungFuJosh]

Better quality, and the best option for ROHS compliance.

Thanks,
Josh

I don't follow the "best option for ROHS compliance" ?

The finish is either ROHS compliant or not.

I missed a slash. Best option / for ROHS compliance. I guess also because I like overkill.

Thanks,
Josh

[b_force]

Better quality, and the best option for ROHS compliance.

Thanks,
Josh

I don't follow the "best option for ROHS compliance" ?

The finish is either ROHS compliant or not.

I missed a slash. Best option / for ROHS compliance. I guess also because I like overkill.

Thanks,
Josh

Ha! no worries, yeah that makes more sense.
Nothing wrong with overkill

[KungFuJosh]

Ha! no worries, yeah that makes more sense.
Nothing wrong with overkill

lol, yeah, making sense is good though.

I love overkill when it comes to quality. I'd rather pay a little more than worry about trace quality or anything like that.

EDIT: okay, okay, also because ENIG looks prettier. 

[KungFuJosh]

If anybody is interested in a kit, but holding off because of part availability, let me know what you need. I've got some of the harder to get stuff including KSA1156YS, KSP94, KSP44, LM377T, etc.

I ship USPS Priority- so far it's been $10 within the US, $50 to Australia.

The v7 kit is $200 USD. I can supply and install the SMT stuff on the socket board for an extra $50.

You can see more info including BOMs for the rest of the parts at futracer.com

Thanks,
Josh

[KungFuJosh]

Does anybody have a better idea for a socket labeling scheme?

I'm finally having a proper custom enclosure made, and I will need to label it.

Thanks,
Josh

[KungFuJosh]

Any opinions on this for a socket scheme?




Thanks,
Josh

[KungFuJosh]

I removed 6V6 and added KT88 to the S6 info. I figured that might be a more useful distinction for anybody that doesn't automatically know KT88, KT66, KT120 would work in that socket.

[byoungblood]

Does anybody have a better idea for a socket labeling scheme?

I'm finally having a proper custom enclosure made, and I will need to label it.

Thanks,
Josh

I would suggest using the standard EIA basing ID along with a couple of tube type examples. For instance, the octal socket on your tracer uses the 7AC basing, 12AX7, etc, uses 9A, etc..

 All of my RCA tube manuals have that information with every listing, it would make quick work of looking up TV pentodes that have similar pinouts to EL84s, 6L6s, etc., for the mad scientists out there that want to try to make use out of cheap tubes.

May I also suggest adding a breakout for a top grid/plate cap wire? Also maybe a 2nd octal socket for testing octal dual triodes? Or, maybe use some DPDT relays to toggle the pin configuration of a socket to account for tubes that are near identical to one another save a swapped pin? Thinking about tubes like the 6U8/6AN8/7199. It may add unwanted complexity to the design, but just throwing the idea out there.

What is the process of adding other tubes to the software?

I'm very tempted with the price/features. May sell off one of my tube testers and pick this up!

[KungFuJosh]

I would suggest using the standard EIA basing ID along with a couple of tube type examples. For instance, the octal socket on your tracer uses the 7AC basing, 12AX7, etc, uses 9A, etc..

 All of my RCA tube manuals have that information with every listing, it would make quick work of looking up TV pentodes that have similar pinouts to EL84s, 6L6s, etc., for the mad scientists out there that want to try to make use out of cheap tubes.

May I also suggest adding a breakout for a top grid/plate cap wire? Also maybe a 2nd octal socket for testing octal dual triodes? Or, maybe use some DPDT relays to toggle the pin configuration of a socket to account for tubes that are near identical to one another save a swapped pin? Thinking about tubes like the 6U8/6AN8/7199. It may add unwanted complexity to the design, but just throwing the idea out there.

What is the process of adding other tubes to the software?

I'm very tempted with the price/features. May sell off one of my tube testers and pick this up!

That's a great idea with the EIA basing, thanks! I already found them for those 6 sockets and will change my scheme to include them.

You can certainly make a breakout to mod the sockets if you need to. The tube socket PCB is setup to use PC pin sockets, but if you build your tester with solder tab sockets instead, you could easily implement switching if you want. Just be careful not to make the leads too long, as you don't want to introduce parasitics.

You can add additional sockets if needed, or even skip the socket board if you want, and create your own tube socket scheme. Only word of warning is that the socket board makes it super easy to get good results, and wiring your own socket array requires very careful planning. Needs to be looped, ferrite beads every other socket, etc.

Adding tubes to the software is really easy, and the software already covers a lot of tubes not covered by my socket board. Here's a link to my tube data file that goes with the GUI so you can see what's already there. You can add tubes either in the data.csv file or through the GUI. In the GUI, you can set the test parameters, adjust the pinout, and then click "change" and it will ask you what name to save the tube:




Keep in mind my kit only includes the PCBs and firmware chip, though I am including a few hard-to-get components right now. For the rest of the parts you need, look at the futracer.com site for the BOMs.

Thanks,
Josh

[KungFuJosh]

Here's the updated list, but I likely won't have room to include everything here:

S1:9A: 12AX7, AT7, AY7, 6072, 7025, CV4004, M8137, 6057, B759.
S2:7BD: 6028, 408A, 6AU6.
S3:9AQ: 6BX6, 6BY7, 6F19, 6GK7, 7ED7, 8D6, EF800, EF811, PF818, W719, Z152, Z179, Z329, Z719, Z749.
S4:9CQ: EF86, 6J32P, 6267.
S5:9CV: N709, 6BQ5, EL84, 6P15, 6P14P, 7189, E84L, CV2975.
S6:7AC: 6L6, 5881, EL34, 6V6, 6550, 6CA7, 7581, KT88, KT90, KT100, KT120 and all others with 7AC, 7S, or 8ET base pinout.

Thanks,
Josh

[KungFuJosh]

I made this as a full-size test on some scrap wood:



I might make the legend text slightly larger, but I think it looks pretty cool.

Dimensions are 9 inches tall, by 7.5 inches wide. I have a second version for custom panels to go with a longer Hammond box (8x12). Not sure if I'll make those or not though.

Thanks,
Josh

[KungFuJosh]

I made the legend text bigger, and added more to the 9CQ socket info.