Re: Plasma Tweeter

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: dhmccauley-at-spacecatlighting-dot-com 

Jim,

The plasma tweeter works as follows.  The high voltage arc is power
modulated.  This modulation (or varying of) of the power directly changes
the temperature of the surrounding
air causing it to expand and contract which then creates sound waves.  There
are two types of plasma tweeters.  Vacuum tube based, and solid state based.
The vacuum tube based
plasma tweeter (which are what most commercial tweeters utilize) are
basically very small and compact vacuum tube tesla coil circuits.  The solid
state based plasma tweeters either use
full-bridge type switching circuits utilizing Class-D PWM or similar
operation (such as the PlasmaSonic system) or also systems which use
high-side modulation where the full-bridge switches
at the secondary coils resonant frequency and the supply rail powering the
full-bridge is being modulated.

Solid state plasma tweeters and low-to mid range solid state plasma speakers
have been built by a number of individuals from this group already.  I have
done extensive work on building
a full-range solid state plasma speaker and have to date created a very
impressive stereo plasma speaker system which I call the PlasmaSonic.  You
can get details on both my initial PlasmaSonic I
plasma speaker as well as the second iteration which is called the
PlasmaSonic II.  Audio reproduction as well as the visual effect of the
dancing plasma must be seen and heard to be appreciated.

Here are the links:

PlasmaSonic I - Full Videos, Pictures, Schematics, Part Lists, Powerpoint
Presentations, and more ! ! !
http://www.spacecatlighting-dot-com/teslacoil15.htm

PlasmaSonic II
http://www.spacecatlighting-dot-com/sstccoil02.htm

If you are interested in building a plasma speaker system, I still have a
number of boards available which are $50.00 each.  See the PlasmaSonic II
link above for schematics, parts list,
assembly instructions, and operating instructions.  A number of individuals
from the TCML have already purchased these boards and have gotten excellent
results.

The following links show others using the PlasmaSonic.

Steve Ward's PlasmaSonic I System
http://hot-streamer-dot-com/srward16/SSTC3.htm

Dave Trimmel's PlasmaSonic System - Video (7MB)
http://209.210.231.220/webdoc2.htg/SSTC/audio%20mod1.wmv

Regarding your question about tubes vs. solid state . . . .  Using tubes
will produce fuller, more richer sound and also allow you to easily run at
very high frequencies.  Operation of 3MHz+ is
a must if you want your plasma speaker to have no background hiss noise.
Currently, the practical limit of solid state coils utilizing class-D
full-bridge technology is about 500kHz.  I have
some prototypes i'm working on that go past 10MHz but i still have lots of
bugs to work out on these before i post any finished details.  However, even
a solid state coil operating at
300kHz will sound very impressive considering where the sound is coming
from.

Dan

 > Hi all,
 > Tomorrow I will attempt the infamous plasma tweeter, my question is, how
 > does this thing work?  It has no primary and only an input voltage of a
few
 > hundred volts, yet maintains a plasma flame large enough to be heard at
 > 80dB!  Has anyone here built one of these, could it be done without tubes,
 > or are tubes best suited for the job...?
 >
 > Regards - Jim Mitchell
 >
 >
 >
 >
 >