DIY 2m radioamateur RF tube amplifier 1975 teardown

[@MENSA.lady2]

The QQE06/40 valve was in common use in home brew 2 metre amps in the 1960's amd 70's good for about 100 watts out in SSB mode.

[@TeardownOZ2CPU]

I hope i can get a working tube for my collection one day :-) now i got two broken, not as funny when my kind of tube collector game is about only having tubes that works.

[@jonscally2349]

nice one Thomas...

[@petercalum9767]

These multi connecors were used in analog telephone exchanges many years ago 😀😀 also matches with the logo you show in the last part of the video. And if the plate voltage goes out there it's 600V DC. I have also build such a 2M PA trin with the same tube back then, looking like this...

[@TeardownOZ2CPU]

that makes sense, i think those connectors are not designed for that high voltage safely. but people can do what they want at home

[@petercalum9767]

@@TeardownOZ2CPU No, it was only 48V for these connectors. They were used interconnecting the racks in the exchange.

[@tpa6120a2dwp]

A relatively simple way of making this or similar PAs where power supply and amplifier are split a lot safer, is to include a low voltage safety loop circuit in the big connector + cable that carries the high voltage such that when the cable is disconnected, the loop is opened. In the power supply this can then be used to disconnect the high voltage and discharge the capacitors safely via high voltage relays. This makes it impossible to have high voltage on the exposed terminals. The safety loop can also be wired to interlock switches mounted to the case lid/walls, thermal cutouts, arcing detector circuits etc.

[@TeardownOZ2CPU]

VERY good idea, it can even be made by checking for filament current is nominal, open or short = ANODE supply off..

[@splitprissm9339]

Second best option: big and bright warning label!

[@splitprissm9339]

And "that is how you go to the hospital" might be the appropriate warning label here....