Re: [TCML] Audio modulated coils: where to start?

["DC Cox" <resonance@xxxxxxxxxxxx>]

We will also be selling complete driver boards with on-board audio driver.
They should be ready mid-July.

Dr. Resonance




On Fri, May 30, 2008 at 10:37 AM, Curtis Cherry <willworkforgas@xxxxxxxxxxx>
wrote:

> Hello everyone.  My name is Curtis Cherry
>
>   Let me start out by saying that I have not ever actually built a tesla
> coil, but I have been researching them for over a year now.  I have
> concentrated on the SSTCs because I too intend to audio modulate some day.
> If fact my interest in tesla coils was spurred by the video of Steve Wards
> DRSSTC2 on you tube playing super mario brothers.
>
>   As I said Ive never built a tesla coil but I will share the info I have
> learned.  Most of the info comes from Steve Wards site www.stevehv.4hv.orgJust click on musical tesla coils.
>
>   There are 2 basic forms of audio modulation.  Amplitude Modulation is the
> first type.  It works by changing the duty cycle of the output of a coil
> while it is oscillating at its resonant frequency.  This changes the amount
> of total power going into the coil.  Changing the amount of power going into
> the coil changes the volume of plasma being produced which in turn causes
> the air to contract and expand.  This creates pressure wave that we hear as
> sound.  This technique works the best with a CW(Carrier Wave) coil.  The
> amount of total power in CW mode is quite considerable and I am not sure if
> anyone makes silicon that handle the amount of power it would take to make 2
> foot sparks for any considerable amount of time.  This type of coil is
> capable of faithfully reproducing audio.
>
>   The second method of audio modulation is PRF (Pulse Repetion Frequency).
> This coil fires "bursts" of plasma out at certain frequencies to create
> pressure waves.  This type of coil suits itself well to any pulsed type of
> tesla coil such as DRSSTCs.  This is the type of coil you want to build if
> you want big sparks due to the lower average power output, but the audio is
> quite a bit more harsh and doesnt lend itself to playing "complex" tones.
> Steves coil runs off of a microcontroller to create the pulses but it would
> work just about as good to use a "zero-crossing" circuit hooked to a
> keyboard or any other audio source.
>
>   You can also get some good info from A guy names Dan McCauley (Sorry if I
> spelled it wrong).  His site is www.easternvoltageresearch.com He sells TC
> driver boards if you dont want to start from scratch.  He also sells audio
> interfaces that can work with any type if SSTC.  And boards for an audio
> modulated coil called the "plasmasonic".
>
>   Please keep in contact with me throughout the process of planning and
> constructing your coil so that we can share ideas and information.  I have
> accumulated all the parts to build my coil and will start half-bridge
> construction soon.  Good Luck to all.
>
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