Thank you so much for the praise! I'm glad you're enjoying the videos!

There's a surprising amount of good deals for random tubes showing up on eBay and other places. Keep in mind, the tubes aren't necessarily desirable tubes, especially within in the audio community, but for playing around and building random circuits, it's perfect!

One of the great things about hobby-engineering is that there's always a good supply of nerds around to buy your old garbage. :) In my own lab, I have an extensive collection of "other people's garbage" ;)

Thanks for watching! And, yup, by connecting the suppressor grid and screen grid to the plate, you essentially end up with a triode that has an oddly shaped plate. But, it drastically changes the characteristics of the tube and you can take a pentode that normally has a sharp cutoff and make it react like a triode with a much more linear response. This is a pretty good resource on the different ways you can hook up a pentode as a triode: www.audiodesignguide.com/New2A3/ETF06TS.pdf

Thank you for checking the video out!

That's actually in the works! I've got an old HP signal generator in the garage that needs a bit of restoration, so once we clean that up, I want to use it to see how fast we can push the tubes before they start running into issues.

Thank you so much! I was actually just thinking about that last night as I finished up editing the next episode about the heptode (which goes up tonight!). Unfortunately, I don't have a good beam tetrode tube in my collection to experiment with on the breadboard. One of these days I'll get my hands on one and we'll see what we can do at 24V though!

Thank you so much! That's awesome to hear that my videos are helpful! To plug them into the breadboard, I just use a standard "belton" style tube socket that I salvaged out of some old electronics, solder on some 22 AWG wire to each of the connectors, and then bend the wire so that the pins end up in a line. Here's a closer photo of the socket: i.postimg.cc/kMW72bcr/IMAG3143.jpg Bent like that, it works out really well with pin 1 being on the left and pin 7/9 being on the right. I would say you could probably get away with about up to 100VDC through a breadboard and this connector if you're being careful, but I'm not sure I'd recommend it, haha.

@@UsagiElectric sorry about my silence... Busy days, thanks a lot again for all the info.

Thank you, I'm glad you liked the video!

My power supply is setup with the positive of the 24V supply hooked up to the plate, then the negative of the 24V supply hooked up to ground. To get -12V I hook the positive of my 12V supply up to ground and then use the negative of the 12V supply to get my negative voltage. Essentially just like explained here: forum.digikey.com/t/get-a-positive-and-negative-voltage-output-from-power-supply/10593

@@UsagiElectric Thank you for your honest answer. May I recommend you always draw the full circuit, including the power supply as to avoid confusion? I understand people now even say that labeling the ground as negative is okay, but according to science it’s actually positive.

Hmm, both the GI7B and 2C39 are transmitter tubes it seems, so I’m not sure how well suited to power supply operation they would be. I’m really unfamiliar with transmitter tubes. But, the GI7B looks like it should be able to do about 170mA at 2kV, which is quite a lot of power. Of course, how you build the supply will depend mostly on the type of transformer you have. For 2kV, you’ll need about 1.5kV RMS. With a big enough transformer, that should be possible. Otherwise, you’ll need to go with a flyback design. The best thing I can suggest is to look at old oscilloscope schematics and see how they generated the HV for the CRTs, there’s a lot of excellent designs floating around there! Google Translate: Hmm, les GI7B et 2C39 sont des tubes émetteurs, semble-t-il, donc je ne sais pas à quel point ils seraient bien adaptés au fonctionnement de l'alimentation. Je ne suis vraiment pas familier avec les tubes émetteurs. Mais, le GI7B semble pouvoir faire environ 170mA à 2kV, ce qui est beaucoup de puissance. Bien sûr, la façon dont vous construisez l'alimentation dépendra principalement du type de transformateur dont vous disposez. Pour 2kV, vous aurez besoin d'environ 1,5kV RMS. Avec un transformateur assez gros, cela devrait être possible. Sinon, vous devrez opter pour une conception flyback. La meilleure chose que je puisse suggérer est de regarder les anciens schémas d'oscilloscope et de voir comment ils ont généré le HV pour les CRT, il y a beaucoup d'excellentes conceptions qui flottent là-bas !

Yeah, I've gotten pretty lucky in finding nice large lots for affordable prices on eBay. I think currently I have around 500 6AU6 tubes in my possession, which should be enough for most of the tube microprocessor project I'm working on!

@@UsagiElectric Cool, Looking forward to seeing the full build.

Haha, don't worry, it's a mess just outside of the camera shot!