Indalhc, did you check out the threads discussing the glow-discharge Plasmatronic designs and my proposed modifications? I've done some work on this since, and the MHCD provides for a very stable and controllable plasma. If, instead of Dr. Hill's arrangement, a planar surface covered with an MHCD grid is created, full range becomes possible.
Hill's design and implementation were the best of the so-called plasma speakers, and could be crossed over at 700 Hz. The big disadvantage is the helium, but my idea to use MHCD instead of simple cathodes eliminates this (the disadvantage of my proposal is the need for exotic materials; I'm using sapphire for the insulator, and platinum plated tungsten for the electrodes; these can be substituted with single-crystal magnesia and platinum plated molybdenum or tantalum, respectively).
I've just run DC discharges this far, dropping about 2 kV across the discharge (couple hundred mA per channel), and haven't applied audio modulation yet, because I have not had the time and design help to make the amplifier. I expect to get back to working on this project during the summer, so I'll post updates and pictures then.
Hill's design and implementation were the best of the so-called plasma speakers, and could be crossed over at 700 Hz. The big disadvantage is the helium, but my idea to use MHCD instead of simple cathodes eliminates this (the disadvantage of my proposal is the need for exotic materials; I'm using sapphire for the insulator, and platinum plated tungsten for the electrodes; these can be substituted with single-crystal magnesia and platinum plated molybdenum or tantalum, respectively).
I've just run DC discharges this far, dropping about 2 kV across the discharge (couple hundred mA per channel), and haven't applied audio modulation yet, because I have not had the time and design help to make the amplifier. I expect to get back to working on this project during the summer, so I'll post updates and pictures then.
Member
Joined 2003
Nixie,
Rather than wait for an amp design, a quick & easy way to modulate a DC arc is to drive a tube output transformer in reverse. Transformer secondary to SS amp, primary in series with DC (depending on config, ground side may be better/safer).
Would you provide a link to the thread you mention?
Regards,
Paul
Rather than wait for an amp design, a quick & easy way to modulate a DC arc is to drive a tube output transformer in reverse. Transformer secondary to SS amp, primary in series with DC (depending on config, ground side may be better/safer).
Would you provide a link to the thread you mention?
Regards,
Paul
96kfps HoloFi [a Open Source / public domain soft- and hardware project]
Yes and interesting. And I'll have to read your post again later and get back to this.
I am now almost certain that we can have a plasma transducer connected as in a
class-A vacuum tube based amplifier, with transducer and amplifier sharing the same space.
The B+ could be somewhere around 30-40kV.
More Fairy Tales...
Some of what a audio plasma (not necessarily plasma, any transducer that will be
practical to miniaturize so that (say) >36 individual units/audio pixels will fit within a
1 square inch area, plasma is here just my best bet) wall eventually should be
able of making - The picture:
Zoom into the strings of a plucked bass guitar, now close - the string appear to swing
all the way from the floor to the roof. The 'audio plasma pixels follows this motion exactly
in 3D, this is again based on a monophonic original recording (at practically any discernible
quality) of the instrument.
All the rest i shaped in software, based on the 'instrument dna', running through a
model that contain all the rest of this particular instrument's specific data and
characteristics.
Video graphics cards would be a natural choice for the audio plasma driver, operating at a
4000 x higher frame rate...
Nixie said:
Yes and interesting. And I'll have to read your post again later and get back to this.
Paul W said:
I am now almost certain that we can have a plasma transducer connected as in a
class-A vacuum tube based amplifier, with transducer and amplifier sharing the same space.
The B+ could be somewhere around 30-40kV.
More Fairy Tales...
Some of what a audio plasma (not necessarily plasma, any transducer that will be
practical to miniaturize so that (say) >36 individual units/audio pixels will fit within a
1 square inch area, plasma is here just my best bet) wall eventually should be
able of making - The picture:
Zoom into the strings of a plucked bass guitar, now close - the string appear to swing
all the way from the floor to the roof. The 'audio plasma pixels follows this motion exactly
in 3D, this is again based on a monophonic original recording (at practically any discernible
quality) of the instrument.
All the rest i shaped in software, based on the 'instrument dna', running through a
model that contain all the rest of this particular instrument's specific data and
characteristics.
Video graphics cards would be a natural choice for the audio plasma driver, operating at a
4000 x higher frame rate...
38 bit 96kfps Holo-Sound [a Open Source, public domain soft- and hardware project]
This sounds pretty interesting, and I hope we can continue some of these discussions over here.
On the previous plasma discussions: With a Biefeld-Brown effect based tranducer, I believe we could
have an all new fresh start. The eccentric? gases within electrostatic designs, all that sounds very complicated.
I wish for simplicity, and also 3D. The time for this could be right.
About the platinum coating. We are at these voltages possibly moving beyond the 'problematic' [oxygen- and nitrogen-]
reactive levels where instead the electrons starts floating above the materials, maybe we can make use of simple
polymers for at least some of the electrode material. To avoid ozone production the emitting anode should have a specially broadened (and still aerodynamic) surface.
The frequency range of this plasma wall. Say that we have a 17 bit resolution on each 'audio pixel', a 10 bit resolution in
height and a 11 bit in width. We then have a total resolution of 38 bit 3D. With this one can effortlessly create
infrasound, 3D infrasound even d:
Nixie said:
This sounds pretty interesting, and I hope we can continue some of these discussions over here.
On the previous plasma discussions: With a Biefeld-Brown effect based tranducer, I believe we could
have an all new fresh start. The eccentric? gases within electrostatic designs, all that sounds very complicated.
I wish for simplicity, and also 3D. The time for this could be right.
About the platinum coating. We are at these voltages possibly moving beyond the 'problematic' [oxygen- and nitrogen-]
reactive levels where instead the electrons starts floating above the materials, maybe we can make use of simple
polymers for at least some of the electrode material. To avoid ozone production the emitting anode should have a specially broadened (and still aerodynamic) surface.
The frequency range of this plasma wall. Say that we have a 17 bit resolution on each 'audio pixel', a 10 bit resolution in
height and a 11 bit in width. We then have a total resolution of 38 bit 3D. With this one can effortlessly create
infrasound, 3D infrasound even d:
Paul, it's not an arc, but a glow discharge. Nonetheless, the transformer idea will still work. However, I don't have a transformer with sufficient insulation (except, of course, the power transformer itself).
Relevant information:
Hill's patent: 4,219,705 -- this is the foundation. However, due to the patent's age, Hill didn't do numerical simulations and instead used simplifiying assumptions in his analytical calculations. Nonetheless, the actual speakers he produced are proof that the approximations are pretty good. An especially important thing to note in the patent is the need for certain features of the plasma geometry. The other is that instantaneous pressure change (sound) is proportional to instantaneous input power change (assuming period is insufficient for new equilibrium to be established). Use www.pat2pdf.com to get a PDF version of the patent.
MHCD stuff: "Direct Current Glow Discharges in Atmospheric Air" (IEEE Transactions on Plasma Science, Vol. 30, No. 1, February 2002) and "Formation of Large-volume, High-pressure Plasmas in Microhollow Cathode Discharges" (Applied Physics Letters Vol. 82, No. 19, 12 May 2003). These are accessible from any university library that has subscriptions to the ejournals. My idea is to use a row of MHCDs to drive the main discharge. A single linear MHCD is possible, but that leaves no trivial way to enforce even current density distribution. Diagram from one of the papers: http://www.diyaudio.com/forums/attachment.php?s=&postid=471470&stamp=1094776019
I-V of different discharges: http://www.diyaudio.com/forums/attachment.php?s=&postid=454537&stamp=1092096285
Suitable output tubes (enough to drive all cathodes of a channel, but current sharing resistors are needed, as well as blowers for the forced air cooling): http://www.wakamatsu-net.com/cgibin/biz/18020011.jpg
Relevant information:
Hill's patent: 4,219,705 -- this is the foundation. However, due to the patent's age, Hill didn't do numerical simulations and instead used simplifiying assumptions in his analytical calculations. Nonetheless, the actual speakers he produced are proof that the approximations are pretty good. An especially important thing to note in the patent is the need for certain features of the plasma geometry. The other is that instantaneous pressure change (sound) is proportional to instantaneous input power change (assuming period is insufficient for new equilibrium to be established). Use www.pat2pdf.com to get a PDF version of the patent.
MHCD stuff: "Direct Current Glow Discharges in Atmospheric Air" (IEEE Transactions on Plasma Science, Vol. 30, No. 1, February 2002) and "Formation of Large-volume, High-pressure Plasmas in Microhollow Cathode Discharges" (Applied Physics Letters Vol. 82, No. 19, 12 May 2003). These are accessible from any university library that has subscriptions to the ejournals. My idea is to use a row of MHCDs to drive the main discharge. A single linear MHCD is possible, but that leaves no trivial way to enforce even current density distribution. Diagram from one of the papers: http://www.diyaudio.com/forums/attachment.php?s=&postid=471470&stamp=1094776019
I-V of different discharges: http://www.diyaudio.com/forums/attachment.php?s=&postid=454537&stamp=1092096285
Suitable output tubes (enough to drive all cathodes of a channel, but current sharing resistors are needed, as well as blowers for the forced air cooling): http://www.wakamatsu-net.com/cgibin/biz/18020011.jpg
Member
Joined 2003
Nixie,
DC voltage on the audio transformer can be minimized by putting the transformer in the ground return of the DC power supply. That way, the only DC the audio transformer sees is that caused by the drop of relatively low current flowing through the low DCR of the transformer. (Should be safer for you and the transformer.)
You may be on to something with MHCD. After hearing the Hill tweeters at a show in Chicago around 1980, I experimented with 3KV DC arcs modulated by both TV horizontal sweep tubes and transformers. Both approaches worked with the arcs and, as you say, should work with a glow discharge. I think it would also be interesting to try more modern technology like PWM.
Ozone aside, the problem I couldn't solve was distributing the discharge over a large enough area to be a truly useful radiator. (Egg shaped flame about 0.5" in diameter by 1.5" tall.) One of the charts you linked illustrates this quite well...I could never get below the glow/arc transition region. So keep plugging away...you may actually get there with MHCD!
Paul
PS to others: If you aren't experienced with high current, high voltage, don't try this! You can get dead so fast only your family will know it!
DC voltage on the audio transformer can be minimized by putting the transformer in the ground return of the DC power supply. That way, the only DC the audio transformer sees is that caused by the drop of relatively low current flowing through the low DCR of the transformer. (Should be safer for you and the transformer.)
You may be on to something with MHCD. After hearing the Hill tweeters at a show in Chicago around 1980, I experimented with 3KV DC arcs modulated by both TV horizontal sweep tubes and transformers. Both approaches worked with the arcs and, as you say, should work with a glow discharge. I think it would also be interesting to try more modern technology like PWM.
Ozone aside, the problem I couldn't solve was distributing the discharge over a large enough area to be a truly useful radiator. (Egg shaped flame about 0.5" in diameter by 1.5" tall.) One of the charts you linked illustrates this quite well...I could never get below the glow/arc transition region. So keep plugging away...you may actually get there with MHCD!
Paul
PS to others: If you aren't experienced with high current, high voltage, don't try this! You can get dead so fast only your family will know it!
38 bit 96kfps Holo-Sound [a Open Source, public domain soft- and hardware project]
Any thoughts on the 'triode coupling' of the plasma tranducer?
I want DDD, (true-) 3D etc here
Sorry about my sloppy editing. Remember this is the Biefeld-Brown thread - with the B+ at 40 kV etc etc, polymer electrodes (read as in wall paper).
Foremost, could someone confirm they understand what I try to say with the triode coupled high voltage plasma transducer (?)
PS. There is absolutely no glow or corona discharges involved in the BB plasma transducer - the way I see it. The early prototype operates at 193 nano Amperes exactly.
Also a lot of air should be able to pass through this transducer - the suggested MHCD cathode could be an obstacle.
Nixie said:
Any thoughts on the 'triode coupling' of the plasma tranducer?
el`Ol said:
I want DDD, (true-) 3D etc here
Paul W said:
Sorry about my sloppy editing. Remember this is the Biefeld-Brown thread - with the B+ at 40 kV etc etc, polymer electrodes (read as in wall paper).
Foremost, could someone confirm they understand what I try to say with the triode coupled high voltage plasma transducer (?)
PS. There is absolutely no glow or corona discharges involved in the BB plasma transducer - the way I see it. The early prototype operates at 193 nano Amperes exactly.
Also a lot of air should be able to pass through this transducer - the suggested MHCD cathode could be an obstacle.
MCSD (MHCD sustained discharge) is a triode configuration. See the diagrams I posted. The MHCD controls the main discharge; you can control the MHCD through either of it's two electrodes (analogy with tubes is grid and cathode driven).
MHCDs perform best with forced gas flow, though it's not necessary.
My idea for a full range driver would be something like a one-sided Pass' Ionic cloud or whatever it was called, except instead of using a dark corona discharge, you'd use a large 2D array of MHCDs. Would work as either MHCDs alone, or with a front grid, as MCSDs. Surface design needs to deal with rear reflections.
All of these very high voltage designs have as a problem ozone and NOx (unless you go Hill's way and use a noble gas). A catalyst-plated mesh covering can deal with these. The visible discharges also emit UV. I've not come up with any way to deal with this. A curved horn can do it, but I feel it's a horrible solution. I can't think of any screen that would block UV yet be sufficiently transparent to sound so that quality wouldn't fall to that of mass-based drivers like ESLs.
MHCDs perform best with forced gas flow, though it's not necessary.
My idea for a full range driver would be something like a one-sided Pass' Ionic cloud or whatever it was called, except instead of using a dark corona discharge, you'd use a large 2D array of MHCDs. Would work as either MHCDs alone, or with a front grid, as MCSDs. Surface design needs to deal with rear reflections.
All of these very high voltage designs have as a problem ozone and NOx (unless you go Hill's way and use a noble gas). A catalyst-plated mesh covering can deal with these. The visible discharges also emit UV. I've not come up with any way to deal with this. A curved horn can do it, but I feel it's a horrible solution. I can't think of any screen that would block UV yet be sufficiently transparent to sound so that quality wouldn't fall to that of mass-based drivers like ESLs.
38 bit 96kfps Holo-Sound [a Open Source, public domain soft- and hardware project]
Now, hearing this (triode coupled) I am more at ease
What is the B+ ?
About ozone generation. One can in fact have a very stable and strong electrostatic high voltage field
- at the same time without any ozone generation or nitrogen reactions (by gradually stepping it up, then set the 'bias motion or flow'. Key here is to operate at very low power/area).
More about the wall. The 3D operating plasma wall could, with the interface described in this
following video http://www.youtube.com/watch?v=zp-y3ZNaCqs (Jeff Han, Multi-Touch
Interaction Experiments) be seen as a whole new musical instrument. I mentioned earlier it
was able to generate infra-waves. It could be set to break the sound barrier also.
An early hardware prototype (driven by a videocard operating at say 120fps) could be good for playing with bass guitar music
Nixie said:
Now, hearing this (triode coupled) I am more at ease
What is the B+ ?About ozone generation. One can in fact have a very stable and strong electrostatic high voltage field
- at the same time without any ozone generation or nitrogen reactions (by gradually stepping it up, then set the 'bias motion or flow'. Key here is to operate at very low power/area).
More about the wall. The 3D operating plasma wall could, with the interface described in this
following video http://www.youtube.com/watch?v=zp-y3ZNaCqs (Jeff Han, Multi-Touch
Interaction Experiments) be seen as a whole new musical instrument. I mentioned earlier it
was able to generate infra-waves. It could be set to break the sound barrier also.
An early hardware prototype (driven by a videocard operating at say 120fps) could be good for playing with bass guitar music
About 2 kV across the discharge. Much less across the MHCD itself.
Current density is quite high, and the plasma is very hot. This lowers efficiency but also decreases distortion, as explained in the patent. I can vaporize tungsten in my experiments, so probably about 6000 K (I can't tell by the color as plasma is not a black body radiator).
Current density is quite high, and the plasma is very hot. This lowers efficiency but also decreases distortion, as explained in the patent. I can vaporize tungsten in my experiments, so probably about 6000 K (I can't tell by the color as plasma is not a black body radiator).
Hello Indalhc!
Here are schematics for a 20kV amp (for the original version without gate). Works with AM. If it doesn`t sound good you could be sure it`s not the amp. But try to stay alive.
Regards, Oliver
http://www.plasmatweeter.de
Here are schematics for a 20kV amp (for the original version without gate). Works with AM. If it doesn`t sound good you could be sure it`s not the amp. But try to stay alive.
Regards, Oliver
http://www.plasmatweeter.de
Looking at the various 'Lifters' that has already been built, it is clear to me that
they are reasonably powerful, simple, functional.
It is difficult to associate any of the above with parts involved in the operation
of a welding machine; carbon dioxide, argon, tungsten, UV-shielding, etc.
The Lifters seem to work well without any special complicated arrangement at
the cathode, or at the anode even (as the main feature being; one electrode
shaped physically different to the other).
If the Lifters radiate Ultra Violet light, then it couldn't really be much more
than that from the sun (even the eventual UV from a big audio plasma wall).
Add a so called 'grid', that is - a third part/electrode situated between the anode
and the cathode of the transducer. Adding this part we now have something we
could name "the plasma transducer-triode" and may at the same time have
a fairly easy task in adding the audio modulator, since this grid may function at
very low voltages compared to the 40kV B+ at the plasma transducer anode.
Could we please try to start from here
they are reasonably powerful, simple, functional.
It is difficult to associate any of the above with parts involved in the operation
of a welding machine; carbon dioxide, argon, tungsten, UV-shielding, etc.
The Lifters seem to work well without any special complicated arrangement at
the cathode, or at the anode even (as the main feature being; one electrode
shaped physically different to the other).
If the Lifters radiate Ultra Violet light, then it couldn't really be much more
than that from the sun (even the eventual UV from a big audio plasma wall).
Add a so called 'grid', that is - a third part/electrode situated between the anode
and the cathode of the transducer. Adding this part we now have something we
could name "the plasma transducer-triode" and may at the same time have
a fairly easy task in adding the audio modulator, since this grid may function at
very low voltages compared to the 40kV B+ at the plasma transducer anode.
Could we please try to start from here
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