How to evaluate RF tubes for power and fidelity?
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Join Date: Dec 2005
Location: west lafayette
Quote:
 Originally Posted by wakibaki Compressed fluid? Outstanding. Compressed fluid is like hen's teeth. You wouldn't believe how many arguments I could win if I could only get hold of some compressed fluid. w
liquids aren't compressible?
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 8th April 2010, 01:59 AM #22 russo   diyAudio Member   Join Date: Jan 2008 Location: Coimbra In the theory, yes you can compress liquids, but you would need an gigantic amount of force just to compress then a tiny bit, in the practice if you put liquid water in your car engine you will break a lot of pieces.
Ty_Bower
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Join Date: Mar 2007
Location: Newark, DE
Quote:
 Originally Posted by wakibaki Compressed fluid?
I believe that both gases and liquids are considered fluids. The former compressible, the latter - not so much.

Since it's on topic, plasmas are fluids too.

diyAudio Member

Join Date: Dec 2005
Location: west lafayette
Quote:
 Originally Posted by russo In the theory, yes you can compress liquids, but you would need an gigantic amount of force just to compress then a tiny bit, in the practice if you put liquid water in your car engine you will break a lot of pieces.
Thanks for the feedback

What I was trying to convey, was for the fluid to be at high pressure before it entered the jets. I believe this would maximize the velocity of the fluid droplets being expelled from the nozzles and result in maximum disruption of the boundary fluid layer (ie turbulence) on the thermal interface.

Regardless, would the plasma loudspeaker topology I described (fully insulated w/ ceramics, minus the electrodes) be safe in a home environment (Other than issues associated with Ozone production)? I've considered directing a stream of Helium gas into the area surrounding the electrodes to minimize ozone production. I believe plasmatronics did something similar with their tweeter.
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 8th April 2010, 05:48 AM #25 kavermei   diyAudio Member     Join Date: Jan 2005 Location: Lokeren, Belgium It probably won't be anywhere near safe in the vicinity of pets, children or laypeople. Remember that people will be attracted to it and will want to poke their fingers, or a screwdriver, inside of it. If you make it foolproof, there'll always be a bigger fool. It's kind of like trying to make a high power tesla coil safe for home use. Come to think of it, I once saw a video (on youtube?) of a coiler who modulated his TC with sound. Of course, there were lots of added noises from the spark gap, transformers, and from sparks hitting various parts... Kenneth __________________ Never send a human to do a machine's job. --Agent Smith
diyAudio Member

Join Date: Dec 2005
Location: west lafayette
Quote:
 Originally Posted by kavermei It's kind of like trying to make a high power tesla coil safe for home use. Come to think of it, I once saw a video (on youtube?) of a coiler who modulated his TC with sound. Of course, there were lots of added noises from the spark gap, transformers, and from sparks hitting various parts... Kenneth
This is why significant efforts must be directed towards maintaining a stable plasma. If a stable plasma is formed, we might assume very little distortion.
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"It is a profound and necessary truth that the deep things in science are not found because they are useful; they are found because it was possible to find them."

 8th April 2010, 07:42 AM #27 kavermei   diyAudio Member     Join Date: Jan 2005 Location: Lokeren, Belgium What are your requirements? Bandwidth, SPL? __________________ Never send a human to do a machine's job. --Agent Smith
diyAudio Member

Join Date: Dec 2005
Location: west lafayette
Quote:
 Originally Posted by kavermei What are your requirements? Bandwidth, SPL?
I'm interested in a minimum of 110dB. However, I would prefer 120dB. The transducer should be capable of 20dB transient peaks. If we assume an average loudness of 90dB, we will require 110dB. I would prefer the transducer to be capable of 10dB beyond this level to allow the listener to be a safe distance from it considering the high voltage involved.

As far as bandwidth, I would like its output capabilities to extend down to 500hz to cover a majority of the audio bandwidth. A lower bandwidth limit of 300hz would be VERY desirable as it would extend response into the modal region where Ray acoustics no longer apply. Sources can easily be combined since the acoustic field is tightly coupled.

However, I'm not sure if these constraints are realistic. The plasma will have to be capable of significant displacement. I believe another gas (ex. Helium) must be allowed to flow past the electrodes to keep ozone production at an absolute minimum.
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 8th April 2010, 09:02 AM #29 Sendy   diyAudio Member   Join Date: Nov 2009 All high or mid power tubes are not "normal audio compatible" - very noisy cooling systems etc. Rather good are old style glass tubes GU81, GU81 etc. - free air cooling, 450W anode dissipation.
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Join Date: Dec 2005
Location: west lafayette
Quote:
 Originally Posted by Sendy All high or mid power tubes are not "normal audio compatible" - very noisy cooling systems etc. Rather good are old style glass tubes GU81, GU81 etc. - free air cooling, 450W anode dissipation.
Couldn't significant heat transport be achieved silently with a dielectric fluid cooling system? Alternatively, water could be used as long as the thermal interface possessed a very high dielectric strength. I believe Beryllium oxide would be the material of choice. Heat pipes or heat spreaders utilizing carbon-graphene foam could be used to transport thermal energy to the thermal interface (Beryllium Oxide) by a 2 phase liquid-vapor cooling system. If such a system was achieved, I believe the limitations related to heat dissipation could be primarily ignored.
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Last edited by thadman; 8th April 2010 at 09:14 AM.

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