What do you guys think of my new LED Magic Eye? I have seen a couple versions of a solid state magic eyes but I believe that all of them had some shortcomings. So, I decided to design my own plug and play for my existing EM34, however it could be adapted for almost any other Magic Eye. Here are some pictures and a video.



Next to my crusty 69 years old EM34






Here is a short video with my Philips radio http://www.upss.com/led-me.mp4

Beautiful - I really like that. Would like to see that in my Zenith!
Very creative!
Joe

Looks good so far. How about a photo of it lit up and installed?

Very nicely done! A little bit of a diffuser panel in front of it, and it will look really sharp.

You should make a video of it side-by-side with a real one!

Wow, that is fantastic. Please keep us updated.

Tim

Kudos!

Looks like you have had boards spun...

Consider a kit?

Variation in the front display for other "look" of eye tubes, like the 6T5?

Inquiring minds want to know!!!

This would be great for the plethora of service grade test instruments with eye tubes, that can be barely seen in the shop lighting!

Chas

I am not considering a complete kit, all the parts are practically off-the-shelf. However, I made some extra board sets (Control and LEDs) which is the key for this design and if there will be some interest I will offer them for sale.

Hello Upsss,
very nice job looks like a nice deign and love the circuit board

Can you build them and sell them for about $20? Some people might like one just because it is different BUT most radio restorers will go for an original which is still only $25- 30 unless you make them as replacements for some of the rarer tubes, in which case there is not a large demand - - - YET. Time will most likely make them more valuable.

That is a cool idea!

The only criticism I will give is tying pins 2 and 8 together may be an issue for some radios.
Granted, I understand why its needed. It just wouldn't be a universal solution without maybe a small isolation transformer.

-Steve

I may be wrong but I am not aware of radios without a power transformer and with a magic eye tube.

I had a Pilot 11 tube table model with no transformer. But not very common I guess.

Only the Chinese will be able to build them by the millions and sell them for $20. Don't forget that a magic eye tube is good only for about 1000 hours.

Just saying some radios have a power transformer with a 6.3 volt Center Tap winding for the heaters.

The center tap is grounded.

If pin 2 is grounded as well, then this presents a short across half of the heater winding, putting a strain on the power transformer and reducing heater voltage in half.

A 1:1 transformer handing 6.3 VAC in the milliamp range would be quite small. It may fit in the base of the socket, but some changes would need to be made.

I'm not trying to be a problem, just pointing out a possible "gotcha".

Here is a modification of the schematic. Granted, its rough… sorry about that.

-Steve

I can see a 12v filament winding with a center tap grounded but why would you have a 6v filament with a center tap grounded? Can you show me a schematic like that?

This led eye tube is one of the better ones I have seen.

I agree with Palegreenthumb about a diffuser, if you can find the right one this will be spot on.

Great job.


Kidd

I have tried different diffusers but nothing I had looked better than without any, at least in my opinion. Do you guys thing I should try green diffusers?

It's very common to have center tapped filament windings, to reduce stray hum pickup. The Detrola 147/Truetone D724 is a really popular collector radio, and uses that configuration.

http://www.nostalgiaair.org/pagesbymode ... 003889.pdf

Zenith liked to use center tapped filament windings on their sets as well, the 12 tube 1940 models are an example:

http://www.nostalgiaair.org/pagesbymode ... 024743.pdf

There were also hundreds of series string radio models built with tuning eye tubes. You couldn't directly use this in a series string as a power resistor would be needed to drop the missing filament voltage and maintain continuity in the filament string. Some sort of combination of a power resistor and small isolation transformer such as Steve proposed earlier would be required to make it work.

Well, I was wrong, thanks for the info.

Nicely done in all respects! Not only the boards, and design but your
documentation. Have always wanted to try one of these and would be
very interested in a board set.
Steve