Theoretical Full Range Ribbon Headphones

[fidelia91]

A

A

 

[lcsaszar]

Why not if there are orthodynamic headphones around. But who are willing to wear the step-down transformers on their head?

 

[fidelia91]

Thoughts on achieving transformer-less ribbons?

 

[rayma]

Thoughts on achieving transformer-less ribbons?

Current source amplifier.

 

[fidelia91]

Current source amplifier.

There doesn't seem to be much info on this? Only one guy claiming it works (First Watt) ?

 

[rayma]

There doesn't seem to be much info on this? Only one guy claiming it works (First Watt) ?

Yes, Nelson Pass has some good, simple current source amplifiers you can build that are suitable for a ribbon driver,
with no need for an output transformer.

 

[fidelia91]

Given that headphones need 1-10 mW of power, and that a ribbon might have an impedance of 0.015 ohms or less, what does this mean in terms of impedance matching for headphones? Can DACs in laptops, phones, etc match with that low impedance?

 

[Elvee]

Can DACs in laptops, phones, etc match with that low impedance?

Obviously, not. But modern semiconductors can be persuaded to drive any arbitrary impedance, high or low, with arbitrarily good performance. No problem there, just a focused design exercise, which I estimate 10 to 15% of this forum audience could carry out successfully, thus no big deal.

 

[fidelia91]

To that end, would a class d amp implementation work to drive any arbitrary impedance?

 

[Elvee]

To that end, would a class d amp implementation work to drive any arbitrary impedance?

Even a class D could be made to drive any impedance, but it would be much more costly from a technical perspective: there are additional parameters to take into account, and they complicate the picture. But given sufficient effort and money, it is certainly not impossible

 

[konstantin]

Theoretical Question -

Ribbons are exclusively thought as high frequency / ultra high frequency drivers. Assuming you were able to solve all the implementation problems that plague Ribbons (crossover point, dispersion, degradation of ribbon over time, transformer, etc), and if you had a diaphragm material that was strong enough, could you potentially make a full range 'ribbon' headphone driver?

The reasoning is that if you solve the implementation challenges, you can get a Ribbon in a pair of headphones. And the material was strong enough, it could handle the movement for bass frequencies, and in a headphone setting, wouldn't have to output that much (compared to a full speaker system). Just a hypothetical here.

Actually, true ribbon transducers are subwoofers, not tweeters, that's because they have a much lower resonance frequency than most woofers.
What makes them more suitable as tweeters in loudspeakers is their limited excursion, but, in the case of headphones excursion is not really an issue.

You don't really need a matching transformer, all it's needed is an LM3886 gainclone amp with +-25V power supply, a 4 Ohm high wattage resistor in series with the ribbon and adjusting the LM33886 gain setting to match the ribbon and sound pressure level requirements.

You can even make it a two way system, three rows of magnets, one wide and one narrow ribbon elements in between them connected in series.

I had build such a setup a few years ago and they sounded really impressive.