Comments on: I want to make some art out of 12ax7 vacuum tubes. Does anyone know how to wire them just to glow?

By: Trailcook

Trailcook — Fri, 27 Feb 2009 06:05:14 +0000

I’m with cdf-rom. You’ll get some good dough from selling the tubes.
Also, you will probably be disappointed with your project because the tubes do not glow very brightly but get very hot. Also it will use a lot of electricity.
I recommend you illuminate the tubes with LEDs. They are inexpensive, run forever, and use practically no current.

By: Pretzels

Pretzels — Mon, 23 Feb 2009 18:58:54 +0000

In vacuum tubes, the first number is the filament voltage, for a 12AX7 that is 12 volts. I would poke around with an ohmmeter to find what pairs of pins give continuity. Since the filament voltage is the lowest in the tube, you can put the 12 volts about anywhere without damage. The correct pins will light the tube up. It shouldn’t damage teh tube to use it this way.

By: athiestforthebirthofjesus

athiestforthebirthofjesus — Fri, 20 Feb 2009 08:03:51 +0000

put 6.3 vac across the “filament” termianals

I *think* they are numbers 1 and 2 … take a meter
and read resistances between adjacent pins and where
you find a sorta small R-value, you will likely have located
the ‘filament’

the 6.3 vac should come from the secndary of a transformer since it will draw considerable current

(the pins will be teh “first-two” or the “last-two” depending on how you count from the “gap” in the circular arrangenement of pins on the bottom of teh tube

for safety’s sake, put a fuse in the circuit (or a ckt breaker) you figure out the value depending on how many tubes you light up

good luck

By: cdf-rom

cdf-rom — Tue, 17 Feb 2009 17:33:07 +0000

I sort of wish you wouldn’t do that. Tubes are getting more expensive and harder to find every day. You could probably get a nice bit of change from people who can use them. If it’s just the effects you want, use LED’s with batteries, or little 4 watt nightlight bulbs and run the bulbs at lower than usual power (like through a small step-down transformer) to make them glow just red instead of too bright to look at.

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