Re: audio modulated SSTC

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

Original poster: "S.Gaeta" <sgtporky-at-prodigy-dot-net> 

The best way to modulate anything is by varying the supply voltage with the
audio. You get the bet fidelity that way. I think your idea is probably the
best way to go, but I never worked with SCRs so I don't know how to do it.
The other way to do it is with a modulation transformer. That way sucks
because not only are the transformers expensive and hard to get, but if you
want good fidelity they will be very heavy!

The other effect of supply voltage modulation is that if you get good base
response, you will see huge streamers occur in time with the base! - that is
a really, really cool effect!

Go for it!, and good luck!
Sue


----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Wednesday, February 04, 2004 10:47 PM
Subject: Re: audio modulated SSTC


 > Original poster: "Jim Mitchell" <electrontube-at-sbcglobal-dot-net>
 >
 > Okay the bug has bitten me! (again) and I think I will build an audio
 > modulated SSTC this weekend.  One question.  If I made a self resonant
 > design, then I put an IGBT in series with power to the bridge, and fed
audio
 > to the IGBTs gate, woudl that work?
 >
 > Regards - Jim Mitchell
 > ----- Original Message -----
 > From: "Tesla list" <tesla-at-pupman-dot-com>
 > To: <tesla-at-pupman-dot-com>
 > Sent: Wednesday, February 04, 2004 7:18 PM
 > Subject: RE: audio modulated SSTC
 >
 >
 >  > Original poster: "Ian McLean" <ianmm-at-optusnet-dot-com.au>
 >  >
 >  > Hi David,
 >  >
 >  > I sure would be interested in seeing some details of your audio
modulated
 >  > VTTC.  I am interested in pursuing this more than the SSTC route -
don't
 >  > like the thought of blowing up all those FET's/IGBT's ;)
 >  >
 >  > Rgs
 >  > Ian
 >  >
 >  >  > -----Original Message-----
 >  >  > From: Tesla list [mailto:tesla-at-pupman-dot-com]
 >  >  > Sent: Thursday, 5 February 2004 10:05 am
 >  >  > To: tesla-at-pupman-dot-com
 >  >  > Subject: RE: audio modulated SSTC
 >  >  >
 >  >  >
 >  >  > Original poster: humanb-at-chaoticuniverse-dot-com
 >  >  >
 >  >  > I think AM mod of the rail would be the way to go for
 >  >  > real HiFi SSTC. Truly, the gate modulation is going to
 >  >  > get ok audio, but not quite HiFi. But the results are
 >  >  > realy quite impresive, and Jim, you shouldn't shoot it
 >  >  > down without at least trying it. I only wish I could
 >  >  > get more plasma to modulate! I know from My VTTC work
 >  >  > that a hotter and larger plasma discharge will give you
 >  >  > a deeper more full sounding audio. As it is I am quite
 >  >  > happy with the results, but the better tone control you
 >  >  > have over the audio source the better. A in-line
 >  >  > equalizer would be ideal, but I am happy with my
 >  >  > previously mentioned pre-amp with base and treble
 >  >  > control, works well enough. Sure the heck beats trying
 >  >  > to fight with my audio modulated VTTC everytime I
 >  >  > wanted to play with it!
 >  >  >
 >  >  > Regards,
 >  >  >
 >  >  > David Trimmell
 >  >  >
 >  >  > On Wed, 04 Feb 2004 08:18:51 -0700, "Tesla list" wrote:
 >  >  >
 >  >  >  >
 >  >  >  > Original poster: "Mccauley, Daniel H"
 >  >  >  > <daniel.h.mccauley-at-lmco-dot-com>
 >  >  >  >
 >  >  >  >
 >  >  >  > I wouldn't go so far and say something like that.
 >  >  > SSTC
 >  >  >  > audio modulation
 >  >  >  > is a very worthwhile and rewarding experiment.
 >  >  >  > Performance can actually be very impressive and
 >  >  > quality
 >  >  >  > is quite high
 >  >  >  > despite the fact audio is coming from a high
 >  >  >  > voltage plasma.  For anyone who've heard my stereo
 >  >  > SSTC
 >  >  >  > PlasmaSonic
 >  >  >  > coils in action can attest to that.
 >  >  >  >
 >  >  >  > I've also done some additional work early this winter
 >  >  >  > with the use of
 >  >  >  > parametric equalizers to further refine the audio and
 >  >  >  > ultimately the
 >  >  >  > quality of the playback with a SSTC coil.
 >  >  >  >
 >  >  >  > So in summary, audio modulating an SSTC coil is
 >  >  >  > DEFINITELY worth it.
 >  >  >  >
 >  >  >  > Dan
 >  >  >  >
 >  >  >  >
 >  >  >  > Well I for one would say audio modulating an SSTC
 >  >  > isn't
 >  >  >  > worth it since
 >  >  >  > you only get mediocre sound quality.  Tube driven
 >  >  >  > tweeters run in the
 >  >  >  > 10s of megahertz range.  Having built a tube driven
 >  >  >  > plasma tweeter, I
 >  >  >  > can tell you that the coil that actually steps the
 >  >  >  > voltage up is only 15
 >  >  >  > turns of 16awg solid wire, so it's resonant frequency
 >  >  >  > will be very high.
 >  >  >  > Yes they do use grid modulation, but the tube is
 >  >  >  > already running at
 >  >  >  > around 30mhz to generate the plasma flame, then you
 >  >  >  > just modulate the
 >  >  >  > signal to the coil.  I wonder if there is such a thing
 >  >  >  > that you could
 >  >  >  > use to build a self resonant audio modulated sstc by
 >  >  >  > feeding the output
 >  >  >  > of the comparator to another chip which would also
 >  >  > take
 >  >  >  > the audio input.
 >  >  >  > That way, it could amplitute modulate the input signal
 >  >  >  > from the
 >  >  >  > comparator, which I think would allow audio
 >  >  > modulation,
 >  >  >  >  is there such a
 >  >  >  > thing?  I think he was getting his info from dan's
 >  >  > site,
 >  >  >  > www.spacecatlighting-dot-com...
 >  >  >  >
 >  >  >  > Regards - Jim Mitchell
 >  >  >
 >  >  >
 >  >
 >  >
 >
 >