mr. a.wayne,
an output impedance of 0.025 ohm is reasonably easy to achieve.
that translates to a DF of only 325. so the only other thing the amp needs to be able to do is to stay within the SOA for *current*. Which would be about 28 amps...
As far as transformers "killing the sound" a whole lot depends on the quality of the transformer in question. If the bandwidth is compromised, or the power handling, then absolutely it's going to be far worse. Otoh, direct drive is likely to be a benefit in most situations.
Think of what the DF is going to be with a series resistor and a low impedance like a 0.025ohm load?
an output impedance of 0.025 ohm is reasonably easy to achieve.
that translates to a DF of only 325. so the only other thing the amp needs to be able to do is to stay within the SOA for *current*. Which would be about 28 amps...
As far as transformers "killing the sound" a whole lot depends on the quality of the transformer in question. If the bandwidth is compromised, or the power handling, then absolutely it's going to be far worse. Otoh, direct drive is likely to be a benefit in most situations.
Think of what the DF is going to be with a series resistor and a low impedance like a 0.025ohm load?
Mr Bear,
Think of the distortion when putting a transformer between the amp outputs and your ribbon diaphragm ,think about the hysteresis issues and the time smearing , la, la, la ...
I have subjectively compared and measured with and without , theres a reason why you don't see them used on ribbon drivers for critical listening , if for pro sound etc , then i can see some benefits ...
What about Bear Power, 1ohm should be easy huh ....
Think of the distortion when putting a transformer between the amp outputs and your ribbon diaphragm ,think about the hysteresis issues and the time smearing , la, la, la ...
I have subjectively compared and measured with and without , theres a reason why you don't see them used on ribbon drivers for critical listening , if for pro sound etc , then i can see some benefits ...
What about Bear Power, 1ohm should be easy huh ....
DF is a measure of output impedance of the amp vs. standard 8 ohm load impedance. However, if you run a low Z load from a high Z source, you've got a different situation as compared to driving a load from a very low Z source. It changes among other things the frequency response and regardless of what frequency the driver operates at it still has a "filter" response (bandpass) that corresponds to some Q value. The transient response will be effected by the shape of the filter, its effective Q.
How much, and to what extent folks can decide for themselves.
Regarding my amps, I'd build a purpose built amp to drive a very low Z ribbon.
How much, and to what extent folks can decide for themselves.
Regarding my amps, I'd build a purpose built amp to drive a very low Z ribbon.
88 db with a 2ohm series resistor , dat must be the most powerful neo speaker on the planet ....
It a matter of size
My woofers are these in a 40cm x 200cm H baffle:
Disconetto har HiFi/10-12'' fra SPP-300 - 12'' højttaler til gode priser.
6 pr. side in open H baffle is at least 90db/1w and then lowered 2 db to match the ribbon.
I would never considder a trafo. I should be a big one to handle about 0.1 ohm from the ribbon. But people build anyway...
Look here under "Lautsperecher": .: Michael Gaedtke :. | Röhrenverstärker , MOSFET-Endstufe, EF95, 6Sh1P, Russische Röhren, Hybridverstärker, 6N3P, 1Sh29B, Gitarren-PreAmp, TCA5500, Ribbon, Bändchen-Lautsprecher, Übertrager
Cheers
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Just a question: Is this a potential way of increasing impedance while maintaining a "pure" ribbon:
http://mjalazard.smugmug.com/Other/Apogee-Ribbon-re-build/i-4RkVJRC/0/L/P4030147-L.jpg
(running several smaller ribbons up and down in a parallel configuration)
I'd be worried for it shorting out though.
http://mjalazard.smugmug.com/Other/Apogee-Ribbon-re-build/i-4RkVJRC/0/L/P4030147-L.jpg
(running several smaller ribbons up and down in a parallel configuration)
I'd be worried for it shorting out though.
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Hi,
On the first models, Apogee used etching process and later, transfer to cuting the ribbon traces with exacto knife.
"The tall neodymium ribbon". Part 1
A very good tutorial with nice pics may help
On the first models, Apogee used etching process and later, transfer to cuting the ribbon traces with exacto knife.
"The tall neodymium ribbon". Part 1
A very good tutorial with nice pics may help
I'm getting intrested in building my own ribbons...isn't the limitation with ribbon design about the energy off the back of the ribbon? Doesn't it reflect off the magnet structures and come foward through the ribbon, causing a tiny delay related "smearing" of the original signal? And, isn't this the advantage of the heil AMT, as the energy in the back of the surface has an escape route..? The ribbon design seems easier to build, seems a doable project...
I think you're mistaking a planar for a ribbon, if you're building a dipole ribbon the energy of the back should be equal to that of the front. I couldn't find aluminum foil that was thin enough to give me the required resistance to go completely transformer-less, I've been experimenting with making household foil thinner by using a simple baking soda solution. I've also tried electrolysis, the foil would become very thin but it would burn tiny holes in it. Anyway the foil is about the right resistance now, now I just need to find the carrier foil to prevent it from ripping apart.
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or you go to a art suply store, the gold leaf is verry thin, and there are also silver look alikes that are pure alumnium as thin as you can get. but for a full range that is a problem (size). also i dont think there is any benefit of producing a real full range ribbon, expecially in the bass department .all the fullrange ribbons are actually planars. even apogee. only there mid highs are true ribbbons.
we ca argue about that but they did not produce a supended on top and bottom huge foil with magnets on the side. so its not a true ribbon. although they say it is.
the "silver leaf" should be prety afordable and can be used for small ribbons. the unrolling of foil caps for me a t least never ended up with foil. always metelaized mylar, wierd enough i used bipoleaire rough and smooth caps, even a expensive audincap, wich aparantly is without foil either
we ca argue about that but they did not produce a supended on top and bottom huge foil with magnets on the side. so its not a true ribbon. although they say it is.
the "silver leaf" should be prety afordable and can be used for small ribbons. the unrolling of foil caps for me a t least never ended up with foil. always metelaized mylar, wierd enough i used bipoleaire rough and smooth caps, even a expensive audincap, wich aparantly is without foil either
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Would aluminum leaf be too thin to work (with) its ~1micron thick which is about 16x thinner than standard household al foil.
Paul
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