RE: PWM Controller question

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

Original poster: "David Trimmell" <humanb-at-chaoticuniverse-dot-com> 

Sue, you are indeed correct that bigger sparks will give a better
response to lower audio fr, I have seen this with my
AudioMmodulatedVTTC. But to get really long sparks you will need some
MAJOR power! I was able to get 10" sparks when first starting out with
audio modulation, basically staccato to the base with some major
clipping! But really we don't need really long sparks to get some really
clean LOUD audio, 4-5" plasma discharge will deafen you. If one could
find a way to get a larger more powerful discharge from Dan's
PlasmaSonic and get a way to easily tune to best mode for clean audio,
then we will have something really cool (not that it isn't already
cool)!

Regards,

David Trimmell

-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Wednesday, June 23, 2004 8:23 PM
To: tesla-at-pupman-dot-com
Subject: Re: PWM Controller question

Original poster: Sue Gaeta <sgsparky-at-prodigy-dot-net>

...and that was with a lousy modulation transformer!
I showed my project to a friend of mine who is a broadcast engineer, and
a
high fidelity freak. He is also an amateur radio operator with a home
brew  high fi AM transmitter. Just for sh**s and grins, he connected his

modulator and power supply to my VTTC. The quality of the audio was
unbelievable!

The mod transformer that I have in there now is out of an old military
transmitter which is known for poor quality audio (an ART 13). If I
wanted
good fidelity I would have to use a transformer that was 4 times as
heavy,
and would not fit in my modulator deck! Good high side modulation makes
for
a very bulky, and heavy rig, but the results are indeed cool!

I have this crazy idea that bigger sparks will give better bass
response,
so I would love to see Steve Ward give his interrupter a rest, turn down

the rail voltage half way, and high side modulate that sucker! People
say
it can't be done, but it is done with 50, 60, 100, and 120 Hz all the
time.
Finding a suitable mod transformer that can handle that much current,
and
has the correct impedance match would be challanging, and maybe even
impossible though. Someone once suggested substituting the mod
transformer
with an SCR or something. If someone could come up with a way of high
side
modulation with active power devices in place of a modulation
transformer
it would be great! Even if he settled with driver side modulation, I
would
love to see what kind of audio comes out of a 10 foot arc! The nice
thing
about high side, high fidelity modulation is that throbbing base will
produce long streamers if you are fully modulating (ie: the rail voltage

will peak at double the! supply voltage with no modulation, and then dip
to
0 volts during an audio cycle).
Sue

Tesla list <tesla-at-pupman-dot-com> wrote:
Original poster: "Eastern Voltage Research Corporation"


  > > I think Dan's PlasmaSonic design is good, but I could see some
  > > improvements in using (possibly) rail modulation. Real high power
plasma
  > > audio modulation will be seriously cool! I have seen it while
arcing
  > > something "semi-grounded" to a AM radio station tower many years
past
  > > (don't ask!). My grid modulated VTTC has been the closest I have
seen
  > > yet, but quality was unreliable.

Absolutely. This *is* the way to do it, although high-side modulation is
more involved and requires a lot more
equipment.

Sue Gaeta's high-side audio modulated VTTC was stunning and definitely
out
performed the PlasmaSonic as far as audio quality goes.

Dan