Homemade Valve Vacuum Tube Tester Build - Part 1 

Thank you for the comment. I have limited experience too, but I'm sharing my journey. I've learnt lots from the comments and it's good fun. Definitely go for it.

Thank you for the comment. I'm glad you are using Grant's design. I have some modular improvements planned for mine.

Thank you for the feedback.

I have sensed the increased demand. I do sell a few valves and rectifier valves are in demand along with quality audio valves. There are more people now like me who want to experiment with the cheaper TV valves.

I'm currently looking for one. Have seen some at auction sites but since I'm new to this kind of overwhelming to try and restore one

@@user-nh7uz8xo1t Yes they can be a rats nest of cables. Best to get some electronics experience first. It tends just to be capacitors that need changing, but the sockets on old tester can be worn too.

Many such cases

Thank you for that feedback. I am working on some add ons to improve it. Look out for those.

I would love to have one of those testers, but people ant silly money for the good ones. I hope this video triggered some memories.

I totally agree about the restricted voltage range. I have valves that need 100V on the screen and 250V on the anode. Since I am using banana plugs, I can patch in an external screen PSU. I have one planned with that offers 8V to 300V. I may put in a current meter too to measure screen current. I use this tester most days. Its a fantastic tool and I love using it.

Good to hear and glad you are working with valves.

Thank you very much for the feedback. I know some testers are £1000, but mine was much less and a lot of fun to build. I tend to buy valves and collections and sell the ones I don't need. The tester is useful for that and will pay for itself in the long run.

The batteries are in the reference design by Grant Willis, not mine. I took them out and used separate mains supplies for the meters. I too don't like mixing mains and batteries.

No reason as such, but you really need to accurately measure the 1V differential to calculate GM. I know some constructors have used analogue meters so really your choice. Thanks for the feedback

I left it in from the reference design. It will be doing some filtering, but I would expect you can do without it.

Yes, it is too low of voltage for some valves, but perfectly fine for my valves. I did debate this in video 1 as I had a transformer that pumped up the voltage to 300V. Ideal for some audio vales, but I wanted to get more usable voltages for my collection. I needed 250V tops, 170V ad 90V. It takes about 10 mins to change the transformer if I need to. Great that you found a tester for $50. I’d be wearing rubber gloves if I used it - too scary!

If you need more voltage, you can add more multiplier stages and use the same transformer as well. Valves/tubes don't need a lot of current usually (other than the heaters). Obviously if you are testing high power valves/tubes then a beefier transformer would be required. This circuit is a good reference, but you'd just modify it to suit the valves/tubes you have in your collection, or in the equipment you primarily like to work on.

Glad that you are interested in building a tester. It’s really worthwhile. You want big voltages there and so may struggle to get the current capabilities from a voltage doubler. You will need a meaty transformer at the front end. Another source of transformer may be an old analogue oscilloscope. These tend to have an HT output into voltage doubler cascade to get the 2500V needed on the tube and they are big units. The use of banana plugs has saved this tester for me as I can plug any heater voltages in directly to the tube and also, I have trouble setting screen a voltage different from the plate voltage. Again, using an external power source via the banana plugs has saved me. I will be building a lot of modular add-ons to this tester to overcome these limitations and they will use a multimeter in place if dedicated meters.

@@VintageandReclaimedElect I am a novice at valves, like you my background is digital (I was senior engineer at Roland UK). I am repairing a lot of Fender, Marshall, Mesa Boogie, Laney etc guitar valve amplifiers at the moment, and because valves are so expensive, am going more for NOS valves like Panasonic, RCA etc. It would make sense to buy a used Fender or Marshall mains transformer which can supply voltages to 6L6, EL34, EL84 12AX7 etc. Even broken valve amps are expensive here in Brazil but it would be good to include a simple class A output stage so I can hear the valves! Do you think I am on the right track? I was tempted recently to buy a used Hickok TV3 tester, but it was about 600 quid and a bit overkill, plus didn't seem to test EL34 or 12AX7.

@@delatronics3257 Yes, home build will get get you exactly what you want. I built this as the decent testers were about £600 - £1100. Final build costs for this was about £280. I do need to build some extras though. If you see the right transformer, grab it. The idea of a class A output stage sounds good.

Motion tracking. I will turn it off!

I'm not sure what direction to take that channel or whether I should keep it going. I unlisted the Android development material as they deprecate stuff so fast and I want it to be relevant. I switched to Arduino and other microcontroller controller material and had very few views. So not sure where to go with it.

You should be able to download the schematic of my version of this tester here. github.com/ghallberg-nbtt/vintage_stuff/blob/main/my_version_schematic_tube_tester.jpg. Unless stated, the diodes are 1N4007. The fuse needs to be 500mA rather than 250mA. Be sure to check out Grant Willis' reference design. valveheaven.com/2015/03/an-inexpensive-easy-to-build-diy-valvetube-tester/