Re: Successful SSTC Audio Modulation - SWEET!

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

Original poster: "S Gaeta by way of Terry Fritz <teslalist-at-qwest-dot-net>" <sgtporky-at-prodigy-dot-net>

Congratulations Dan!

I noticed the same thing with my tube coil. When you draw an arc, the hiss
from the corona wind goes away, and the audio has a purer sound from the hot
plasma.

Sorry that you lost a bridge rectifier, but I'll bet it was worth it now! My
tube coil ate a mica cap in the beginning.

Cheers,
Sue

----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Thursday, May 29, 2003 9:46 AM
Subject: Successful SSTC Audio Modulation - SWEET!


 > Original poster: "by way of Terry Fritz <teslalist-at-qwest-dot-net>"
<dhmccauley-at-spacecatlighting-dot-com>
 >
 > After a day of extreme frustration (yesterday gate drive problems) and a
 > simple re-design of my gate drive topology, i finally got my SSTC to run
 > from the push-pull outputs from the
 > TL494.  So now, I have 25% on-side1, 25% deadtime, 25% on-side2, 25%
 > deadtime.  This is required as operating in CW mode consumes mucho power,
so
 > by running the coil
 > this way, you can reduce total output power and improve reliability of the
 > h-bridge switch.
 >
 > Audio was provided by a CD player (high impedance output) and fed into the
 > deadtime comparator pin of the TL494 through an 0.1uF capacitor.
 >
 > Audio output was very clear and almost zero noise otherwise from other
 > harmonics in the arcs.  Very impressive, similar to Sue Gaeta's high side
 > modulation audio quality on her 811A
 > VTTC.  Also, with fan cooling, the heatsinks and FETs never even really
get
 > warm.
 >
 > One note to add, is that to improve audio quality, it is necessary to
 > draw-out a continuous white flaming arc from the toroid.  This can be done
 > by any metallic object and permanently set at about
 > a 2-3 inch gap depending on output power levels.  The result is stunning
 > audio.  (at least stunning when considering its coming from a hot flaming
 > multi-kilovolt arc ! ! !)
 >
 > Also, volume control can be provided by adjusting this discharge gap
 > distance.  To get really loud audio, just try to stretch the arc as long
as
 > possible.  I guess this provides much more heating of the air and
therefore
 > more volume.
 >
 > Awesome!
 >
 > The Captain
 >