Re: audio modulated SSTC

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

Original poster: "Malcolm Watts" <m.j.watts-at-massey.ac.nz> 

Hi Finn,

On 3 Feb 2004, at 20:28, Tesla list wrote:

 > Original poster: Finn Hammer <f-h-at-c.dk>
 >
 >
 >
 > Tesla list wrote:
 > >Original poster: herwig.roscher-at-gmx.de
 > >List,
 >
 > snip
 >
 >
 > >Plasma tweeters use capacitive feedback mostly and  produce a very
 > >good audio quality. However the operating frequency is much higher
 > >than in our TC systems. And the output power is relatively small. Is
 > >the a.m. statement wrong in principle? Any answers and comments are
 > >very welcome.
 >
 > There are a couple of vacuum tube based plasma tweeters, U. Haumann`s
 > being one of them for the self made "person". The oscillator is based
 > on a pentode, where there are more than one grid in the path btwn.
 > kathode and anode. One grid can be used to set up the oscillation,
 > another grid can be used to modulate the output with audio.
 >
 > I think this could be done by varying the supply voltage to the
 > H-bridge: Oscillate with the bridge, audio modulate a big industrial
 > IGBT in the supply rail. It will have to burn up at least 50% of the
 > delivered power, so Therefore a big industrial type is needed, one
 > that is good for dissipating those 1-2 kW`s loss. In this case, a self
 > tuning oscillator would be ideal. (I think) I`l try it out some time,
 > unless someone else does it first, and maby even then.

Sounds like a good case for a modulated SMPS supply on the face of
it. But what happens to the plasma if you drop the output voltage?
Why not just modulate the H-bridge? Am I missing something?

Cheers,
Malcolm

 > Cheers, Finn Hammer
 > >Cheers,
 > >Herwig
 > >
 >
 >
 >
 >
 >