DIY ribbon tweeters

[dondoucette]

So I am going to try a DIY ribbon tweeter, the issue for me of course is impedance, I was looking into matching transformers but for all intents and purposes the ribbon is 0Ω
So what is the strategy for matching that?

Your thoughts are appreciated, and FYI this is just for fun and I am hoping to learn something and it gives me a reason to use my 3D printer.

Thanks
Don

 

[nerdorama]

How did you make the corrugations? For driving them you could make a low voltage high current amp that could drive them directly. I thought about doing this some years ago when I was playing with ribbons.You might also talk to Heyboer or Edcor and see if they would make a custom transformer for you. Bud at Onetics has mentioned to me that he made ribbon matching transformers in the past but I'm not sure he is selling to the DIY community now.
Good luck with your project and keep posting with your progress.
John

 

[smurfer77]

If your ribbon is more efficient than the the proposed mid/bass drivers, perhaps a series resistor with the tweeter to bring it to 3 Ohms or so save you the trouble of needing a transformer?

 

[dondoucette]

I picked up the corrugator from a hobby store, I think a finer corrugation would be better or perhaps embossing the foil.
I’m starting with very cheap/thin foil from the grocery store while I get the assembly figured out. I have some .00045 foil coming. I don’t think I’ll run them below 2K but that will depend on what testing shows. This should be fun.

I’m using my 3D printer to build the housing for the tweeter, this makes prototyping easy and changes are simple. I’m using PETG (Polyethylene Terephthalate Glycol) and 80% infill for strength. I may have to experiment with infill and/or try ABS or other materials depending on resonance.


The print will take 7 hours, then I will assemble and test with a function generator to get an idea of how much tension across the ribbon is required.

 

[dondoucette]

If your ribbon is more efficient than the the proposed mid/bass drivers, perhaps a series resistor with the tweeter to bring it to 3 Ohms or so save you the trouble of needing a transformer?

That is a possibility I just didn’t want to get into big resistors, but yeah it might help balance the drivers.

 

[dondoucette]

Only 6 ish more hours to go...

 

[BinaryMike]

Here's an idea: There is some evidence that toroidal power transformers can work well at high audio frequencies. Assuming that's true, why not make a ribbon tweeter matching transformer out of one by wiring just a 1~2 turn secondary of your own? Antek offers many to choose from, at very reasonable prices. The 25VA size seems to be wound on the same core as the 50VA size and has an unusually large center opening, but I doubt if that matters for this application.

 

[dondoucette]

Here's an idea: There is some evidence that toroidal power transformers can work well at high audio frequencies. Assuming that's true, why not make a ribbon tweeter matching transformer out of one by wiring just a 1~2 turn secondary of your own? Antek offers many to choose from, at very reasonable prices. The 25VA size seems to be wound on the same core as the 50VA size and has an unusually large center opening.

Hmmmm interesting...

 

[dondoucette]

Obviously still a prototype and I need to put the top, bottom and back on but it’s a start...

 

[nerdorama]

What are you planning or using for magnets?

 

[dondoucette]

What are you planning or using for magnets?