Same as western electric did with the 211? ... see here
Western Electric - Rosetta Stone for Triodes
about 3/4 of the way down the page ... don't think I'll get away with one of these in the lounge
Western Electric - Rosetta Stone for Triodes
about 3/4 of the way down the page ... don't think I'll get away with one of these in the lounge
Or it could in fact be an 80 or similar, I had what was obviously an 80 handed to me as a "black plate 2A3" at a show once and had a real job to convince the individual doing so that it was in fact not a 2A3..
As you do with any triode: connect its grid to the cathode (if it is an indirectly heated tube) or to the ground, where the filament will be referenced as well (if it is a directly heated tube) and you get a diode out of it.
@robmil: what seems to be the problem ? Remove the tube, replace it with a series connection of power resistor (to obtain same voltage drop) and a silicon rectifier diode and you're done.
Last edited:
Technically you'll get a diode that way, but in all my years the proper way has been to connect the grid to the plate as pictured in the Western Electric schematic posted by Doz. Not to the cathode.
But this will result in grid dissipation, and could lead to a meltdown and fireworks should remains of the grid make physical connection to cathode
The grid surface area is very small compared to the plate area and almost all of the electrons will miss the grid and proceed directly to the plate. It works fine in any application I have tried, particularly with low mu triodes which have grids with wide spacings.
Your proposed connection may theoretically be worse under high current conditions if the grid actually gets warm enough and starts to emit electrons on its own. In any event its not recommended in any tube design manual I have seen.
Perhaps I'm showing my ignorance here, but what exactly is the point in using a 2A3 as a rectifier? I'm not trying to sound pompous here, mind you. There may very well be a legitimate reason to do so (a potentially lower voltage drop leaps to mind), and I'm hoping someone here could enlighten me...
This doesn't really apply to todays world, but years ago manufactures would sometimes use triodes as rectifiers because they were available as surplus in quantity and probably very cheap. One that comes to mind is my old Heathkit C-3 condenser checker. It uses a 1626 as a half wave rectifier in a doubler. I built it from a kit a looooong time ago. It still works perfect and every so often I bring it out, power it up and use it. Yes, it has sentimental value so I keep it going even though I have better instruments that do the same thing. Personally I would never commit a valuable and coveted 2A3 to lowly rectifier service. Well, maybe a 300B
Marketing; WOW, - a 2A3 PreAmp !!!
MingDa has one...(and a RIAA that use 6N6P as rectifier)
Arne K
Attachments
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.