RE: audio modulated SSTC

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

Original poster: "Mccauley, Daniel H" <daniel.h.mccauley-at-lmco-dot-com> 


Actually, i'll have to recind that statement.  I now have actually found
quality to be better if the arc is allowed to become a brush-like
discharge.  The problem with drawing an arc is that its hard to control
the length and stability of an arc and maintain a stable audio
characteristic.  By increasing or decreasing the arc, the audio
properties are affected to a high degree.

Dan



David,

I suspect that the key is the form of the discharge/brush:

At the frequencies, our VTTCs run, a hissing sound is generated,
degenerating audio quality. As to SSTCs, somebody (Dan?) wrote: "One
note to add, is that to improve audio quality, it is necessary to
draw-out a continuous white flaming arc from the toroid......" Doing
this, the discharge becomes quite, but *WHY*?

At the frequencies, tweeters run, the discharge looks like the a.m.
modified one and the audio quality is better already.

  > But after building one of Dan's Plasmasonics, I have no interest in
 > messing with VTTC grid modulation.
- I'm playing with such a machine as well, but haven't found the optimal
configuration yet. I am planning on reworking the driver circuit.

  > And the recent talk of rail and plate modulation has got me real  >
interested, definatly the holy grail of plasma audio!
- Same to me. Thinking of these new ways of modulation, I unfortunately
found out, that I do not fully understand the "old" classes of operating
RF power amplifiers either:

Class A: conduction angle 360 deg - maximum linearity - no tank
                circuit necessary
Class B: conduction angle 180 deg - fully acceptable linearity - tank
               circuit necessary
Class C: conduction angle less than 180 deg - linearity is extremely
                poor, despite a tank circuit is necessary

The latter statement I do not understand: Why is the linearity so poor?
Because of the flywheel effect the correct waveform should be restored
and Class C *oscillators* do this without problems. How is "linearity"
defined? Maybe I am thinking in wrong terms?

Take care,

Herwig



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Greed is the root of all evil!
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