Tube Prototyping Station

[Gio] enjoys using vacuum tubes in his projects. He designs the circuits using a CAD program but was finding that there is no substitute for actually building a prototype before heading to a final design. To make this process easier, he built his own tube prototyping station.

At the top of the board he’s got three different sizes of tube sockets with the pins from each wired as common. The nine pins from the sockets break out to a terminal strip where they can be interfaced with a solderless breadboard. For added versatility he’s included terminals to tap into some RCA jacks, as well as a 100 kOhm variable resistor. We’d bet this is not something that you can find ready-made, but it sure does look a whole lot better than a workbench full of components alligator-clipped together.

16 thoughts on “Tube Prototyping Station

  1. Wow, I should build one of those… sure beats soldering tag leads to the socket and plugging them into the breadboard, transistor style (like I do now…). I do worry about how much of an effect all that capacitance from the breadboard has on those hi-impedence circuits, though. It’s why I never expect it to sound exactly the same when it’s wired point-to-point. Nice hack, simple and well thought out!

  2. You can find these ready-made…if you’re willing to go back far enough. I used to have a tube breadboarding kit from the ’50s which fit into a large wooden suitcase. It included a variac-adjusted power supply and several drawers of tube sockets and various discrete parts mounted on plastic carriers with metal pins for electrical connectivity. The front of the suitcase was lined with perforated pegboard; you snapped parts into the pegboard and connected the pins with jumper wires. The whole thing was so cumbersome and problematic that I only used the power supply, and eventually junked the rest. (Boo hoo!)

    It really highlights the sea change brought about by transistors; all that junk was obviated by a solderless breadboard you can fit in your pocket. Tube prototyping still requires a lot of fabrication and this guy has done a great job. A++ for literal breadboarding! I’d be concerned about the reliability of a solderless breadboard at typical plate voltages of 150-450VDC though.

    Here’s one of my own tube prototyping aids–a 6.3VAC/300VDC power supply built into some old hard drive cases.

  3. doesn’t look like any high voltage on that setup (not all tubes required HV). I wouldn’t doubt some high current capability with that circuit though. Definitely may be pushing 70% of the breadboard’s capacity on a few lines.

  4. I’m sure there is high voltge over there or that big .47 uF capacitor would be at least 20 times smaller. From its size I guess it’s rated at least for 200-400 volts.
    I you never worked with tubes before and try this arrangement, be very careful with capacitors: if unloaded they can keep their charge for a long time and you can get a shock touching a board that was turned off for days.

  5. I have routinely put 300VDC on cheap breadboads without issue. The trick is to make sure you don’t have any large voltage differences between neighboring columns. As long as you space everything out, there is really no problem. You might notice that this guy has at least 5 columns between every connection. I usually avoid using the rails, but I am not sure that matters too much.

  6. WOW! I Like it.I’m a I’ve got a tube habit myself,and I always end up pulling my hair out at 3 in the morning trying to balance out what should be a perfect bias (or whatever) and I find what’s on paper just doesn’t translate to(my)reality. I guess I should have built one of my own LONG ago. Thanks for the inspiration. Maybe I’ll build two, or one with sockets and transformers for pre and power amp protos. Now-To the coffee pot!

  7. When I was a kid one of the electronics experimenting boxes I received had a breadboard full of holes and spring fixtures to connect the components together solderless. There were no tubes of course due to the thing being oriented to kids, but that arrangement would be very useful for tube prototyping.

  8. @therian, others:

    there most certainly is high voltage on that breadboard. zooming in to the photo, i see the tube is a dual triode with 9 pins, and i’ll bet dollars to donuts it’s a 12A_7 (pins 1 and 6 are the plates).

    others say they’ve had no problems with high vdc on breadboards, but i personally would not feel comfortable with such a situation. i’d also, as others said, worry about the parasitic capacitances.

    the build is nicely done though, very clean and well organized.

  9. Those plug-in boards make for nice distributed capacitance arrays! It would be rough to proto anything of super-high impedance. However, with adequate layout considerations, it could be quite handy! Just don’t try to do anything with DC-to-daylight bandwidth. Or anything with a lot of dv/dt. FRATZ!

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