Driving small full range ribbons

[setmenu]

I am at present experimenting with ribbon transducers for headphone use.
I have built some with etched coil ribbon's and am having good
success with them.
I have done some small experiments with single aluminum strip
ribbons in the early stages of this project but at the time rejected them as being too problematic to drive.

But I am now becoming interested in this approach again.
So I am wondering about the best way to drive them.
The area that is worrying me[among others] is bass control,
as the ratio of ribbon impedance to say an amplifiers output
impedance would be close to 1-1 in a lot of cases.

I realize that ribbons used in conventional speaker setups are not
expected to produce LF.

Just musing here at the moment but certain elements of this approach seem to offer benefits over my present one in some areas.


Any views Here?

Thanks

Setmenu

[jgwinner]

No ideas, but this sounds interesting. How in the world did you build your own? What kind of Aluminum strip?

[fdegrove]

Hi,

You may try etching a highly resitive conductor on a mylar fil in zig-zag to up the resistance.

OTOH,have you consider the weight penalty the magnet strips are going to bring?

Cheers,

[setmenu]

Hi thanks for the responses.
The existing phones use a flat rectangular etched field coil with
18micron .15mm traces on 12micron polyimide substrate.
These work great and I am at present refining the coil further.
[Re the weight issue the phones are lighter than my stax 404s ..just .]

These coils are costly to develop so I was curious as to whether
I could use just plain strips of material rather than photo-etched
foils.
As I have said I tried this at this projects early stages but the
resistance was in the region of well less than .5 of an Ohm.
less then the lead supplying the signal in fact, kinda makes the
amp output impedance academic methinks.
In search of a better ratio[being headphone transducers they obviously do not need huge power handling!] I have done a few
experiments with aluminiumised polyester as used in packaging
but as the quality of plating was not to wonderful I cannot make any claims as to its suitibility..but it does seem to work ok.
There seems quite a choice of metal coated plastics out there
so I will probably obtain some samples.
The sort of Resistance that would make a good starting point I guess would be 2-4 ohm.
I suppose it is down to the ability of the material to cope with a
given power input as I am certain I can obtain plated material with insanely thin deposits so obtaining a usable resistance seems do able.

Anyway this is a tangent I will explore given the time!
As the existing approach is going well at the moment[I have ribbons/coils of 34-70 ohm there!]

So forgive me if i just seem to be thinking out loud here
I am just hooked on transducer design...Dam

Oh heres a pic of the existing phones thus far.


Setmenu

[TroyTanner]

setmenu,

Can you from the details on your source for kapton/foil laminate along with the details of your coil making process?

Best Regards,
tt150001

[martioz]

HI setmenu,

Why not use Air Motion Transformer?
The membrane can be found here:

http://www.simplyspeakers.com/graphi...m_689-1107.jpg

[setmenu]

Hi TroyTanner
The material used is at present an Espanex laminate product.
The coil pattern was drawn up on a PCB development program
and etched by a commercial circuit production company.

Martioz
Thankyou for your suggestion.
When I set about designing a pair of headphones I wished to
produce something that was unique [to the best of my knowledge],Headphones that use a Heil transducer already
exist in the form of a brand named Ergo.

Thanks

Setmenu