building a lit up tube display

[wild]

hey guys,

I'm completely new to all this stuff but I just love the look of glowing tubes in guitar amps and tubes in general and I was wondering i there is a simple way that i could make something which can have tubes that are on just to light up....no actual purpose other than to light up. Basically it would just sit on my tv in the lounge....Does anybody have any suggestions for how i could do this??(just the electronics part of it)

[chrish]

Oh, the horror

[Rob11966]

Yes Chris, it is horrible - horrible beyond description. Yet, I find that I strangely drawn towards providing an answer.....

Wild, you would be much better making something that actually works!

However, to answer you question, the solution is relitively simple.

The glowing part of the tubes are called the heaters. They are similar to a light bulb filament and only require 2 connections. Also, they only need AC current. Even better they run off low voltages; in other words this is relatively safe, although you can set the house on fire of course.

So, choose your tubes then check the tube data sheet to see what voltage the heaters use (mostly 6.3V but it does vary according to the tube). Get a transformer that will supply just the low voltages that you require - a custom made one from somewhere like Edcor might be best. Then you need to hook the heaters (the tube data sheet will tell you which pins to use) in parallel.

Be aware that although the tube heaters use low voltage, they need a lot of current. You will also need quite a few parts, chassis, tube sockets, wire etc plus some rudimentary tools including a soldering iron.

There yo go. If you do put it together, please post a photo. This one I have to see.

Oh the humanity......

Rob

[Robert McLean]

All you need to do is connect the heater terminals of the tube to a power supply of the correct voltage.
So you will need a chassis, a transformer, a tube socket, a tube, and some wire. And solder and a soldering iron. And a power cord. And an electrical power outlet to plug it into.

Pretty simple, I am not sure if I left anything out.

And I just noticed Rob replied so I will stop here,
except to say another approach is to get an old radio or amp and just take the cover off.

[boywonder]

You can use AC or DC voltage for the heaters. In this application, they'll never know the difference.

BTW: the first #'s (for USA tube nomenclature) of the tube is the filament voltage, so a 12AX7 is a 12v filament and a 6SN7 is a 6V filament, etc, etc. Many 12V tubes can also be wired as 6V tubes. Filaments come in many other voltages (read the first digits of the tube #) like 2.5V, 25V, 50V, etc etc.

Hopefully you'll be using tubes that are of no use for audio! (like old TV toobs)

You may want to find some cheap/free tubes that are unusual looking for an even greater aesthetic (non-functioning anode top cap, blue glass, nice glowing colors, etc).

[coldcathode]

Wild,

Best bet is to collect the tubes you intend to use. Then gather all the heater value information. From there group the tubes by heater voltage then heater current.

Many 6V tubes draw the came heater current.

Same with 12V Tubes...some of which have 6V "center tapped: heaters.

For display purposed only limiting the current will probably be a priority so you can purchase transformers from Rat Shack (radio shack) in a couple different voltages to suit your needs.

For instance,

A lot of 6V tubes draw a common 0.3 Amps, you could wire 4 of them in series and use a 25.2V 450mA Tranny like this
25V Rat Shack

The tubes must draw the same heater current when used in series.

There are other CHEAP transformers at RatShack that you can use for various combos.

You can Parallel The same voltages and you ADD current. Voltage stays the same.

In Series the voltages ADD and the currents stay the same (and must be equal since the current will equal the highest in the series)

For even greater Safety you could just get a few Laptop and Flat Panel DC power supplies off of E-pay.

Something like this

You could run more than 20 12V .15A Heaters off this!
You could also make (2) strings of (6) 6.3V .3A heaters in parallel then wire the two strings in series and power (12) 6.3V heaters.

Just learn Ohm's Law and your good to go.

Just remember sockets aren't that cheap and don't use any useful tubes just for a display.

[firechief]

Well wild - Probally the cheapist answer is to find an old tube radio and salvage the parts you need. Tubes, sockets, transformer ect.
If you decide to take a stab at it, you should find one and let folks on the forum know what it is, and we can probally talk you through it, But I worry about you getten shocked.
Of course I survived.

[coldcathode]

But I worry about you getten shocked. Of course I survived.

LOL

That's exactly why I suggested the DC power supplies.

[SpreadSpectrum]

6as7s look really nice lit up, that's what I'd use for a tube nightlight. Also, I think the its the 75V VR tubes light up orange? They look real nice.

[tinitus]

Funny

Well, some people believe strongly in placebo effects and our easily cheated "weak mind", so who knows how your normal SS or classD amp change once the tubes are glowing