Dan's Conventional Tesla Coil

SSTC "Singing Arc" Project

SSTC performing some quality audio modulation.

Introduction

At a recent tesla event, I had the chance to watch and listen to a very nicely made VTTC (vacuum tube tesla coil) and it was

modified to create a "singing arc", or put technically, a tesla coil where the RF output is pulse width modulated so that the contracting

and expanding air actually reproduces the audio signal which is fed through the driver circuit. So, now its my turn to recreate the

experiment using my SSTC.

The audio signal was derived from one channel (either LEFT or RIGHT) of the high impedance (RCA connector) output of a

CD player. This was fed directly in series with a 0.1uF DC blocking capacitor into the deadtime comparator pin of the TL494

PWM Controller IC.

Initial Results

Initial testing of the audio modulated SSTC were very successful. Considerable background arc noise was present when the

SSTC was left to arc off the break-out point placed on the toroid, but when using a ground rod to "pull" a thick, flaming arc off

the toroid, ambient arc noise was almost zero. It is during this "pulling" of a thick, flaming arc that audio quality is very clear and

relatively excellent quality considering the fact its eminating from a high voltage arc!

Schematics and Electrical Design

The following schematics are the current design for this audio modulated SSTC. (Requires Adobe Acrobat 5.0)

Audio Amplifier

The following is a schematic for a simple audio pre-amplifier with adjustable bias setpoint. However, this preamplifier is

not needed for this particular design.

More to come soon . . .

Last modified August 16, 2005 08:05:22 PM