Ribbon headphones

[bear]

You can likely do a credible job using the original diaphragm as a 1:1 mask for photoresist. I'd test the process using something else first, to minimize the handling of the original, to be sure you have good, high resolution photoresist, and you have figured out how to apply it properly and expose & develop it properly.

But the problem is likely to be elsewhere.

Commercially metalized plastic film has the metalization in the thinest possible thicknesses for color only. That means it will be insufficient to handle the power required by a diaphragm.

(PVC is also low temp stuff - maybe you mean polyester/mylar??)

You need a thicker trace on ur new diaphragm than most metalized films will have.

No harm in trying the experiment.

The flex PCB material is an interesting idea, but their thinest is likely too thick (too much mass) for a good diaphragm.

That's why these are usually done by large companies who have the resources to put together the combination of diaphragm material, thickness and trace accuracy and thickness plus the right bonding agent for the foil trace vs. heat.

_-_-bear

[oshifis]

bear,

I see what you mean. The commonly available foil is vacuum metalized indeed, used for flower etc wrapping. Thas has infinite resistance, when measured between any close points. Mine is different, the aluminium layer is relatively thick and it has low resistance at distant points.

BTW, is there any formula to calculate the resistance between two points on an infinite surface? From such measurement one could calculate the alu layer thickness, if the formula were known.

Laszlo

[setmenu]

I have tried using aluminized film myself.
It was from some packaging.
It was giving a low resistance between points and when tested did work.
But the thinness of the film meant very low power handling.
couple this with the relative inefficiency of the driver and the film
failed quite quickly when asked to do any work.
The aluminium definitely needs to be in the order of microns rather Angstroms in thickness!
My target range for copper would have been in the region 3-6 microns depending on trace width etc.
I have only managed to source 9 micron thus on 12 of polymide [adhesive-less] thus far.
Aluminium laminates are a different ball game, had not luck in sourcing anything that was lighter than the copper combo.

[tade]

also, most metalized films are in between two layers of plastic, which would explain the high resistance. The metal actually acts as a gas barrier because comparatively, polymers are extremely porous. That is why the plastic beer bottle has yet to catch on.

[ionomolo]

Two years have happened and it seems nobody did it.

I belive the ribbon headphone would be a truly reference transducer. The only problem is the diaphragm material?

[jzagaja]

There's only one problem - supplier for a foil below 6 micrometers no matter aluminium or plastic or laminate. There some Chinese but who want to take a risk?

[ionomolo]

Originally posted by jzagaja
There's only one problem - supplier for a foil below 6 micrometers no matter aluminium or plastic or laminate. There some Chinese but who want to take a risk?

Well if one can buy in small quantities i would.

Etching a coil makes little sense to me because wires going up would make a force opposite to wires going down. Somebody has suceeded in it?

[jzagaja]

Etching wires make sense for speakers IMHO because you need some gap between them and have a space.

http://www.diyaudio.com/forums/showt...84#post1788584


Capacitor foil isn't bad if you have a right transformer. Otherwise try to ask for double metallization - easy to find locally. Only one layer has ca. 1kOhm (good for a microphone). I had Chinese address for 2-3 micrometer aluminium foil but I don't like Chinese people - they says yes yes yes and nothing happens then.

[setmenu]

Originally posted by ionomolo



Well if one can buy in small quantities i would.

Etching a coil makes little sense to me because wires going up would make a force opposite to wires going down. Somebody has suceeded in it?

You can see how i did it in this thread:


Ribbon or planar headphones