Audio Modulated DRSSTC: It has begun

[Amphiprion]

I wound my first Tesla coil secondary today. This is for the first try at a dual resonant solid state driven Tesla coil that will be audio-modulated to produce sound. It was quite a lot easier to wind the secondary than I expected. The picture attached is a 3.5" x 15.25" air core secondary coil wound on 3" SCH40 PVC pipe with approx. 700ft of 24 gauge enameled magnet wire. I intended it to be 18" long, but the wire kinked and got tangled towards the end, so I cut it short and wound up with 9mH inductance instead of the 10+ I had hoped for. It's nothing that can't be made up for with a larger top load capacitance though.

Anyway, this is just the start of a looong journey. Here's the secondary coil drying over a trash can after the second coat of lacquer to set the coil form. I managed to do all this winding with just a cordless drill and my hand to provide wire tension.

[wigginjs]

The winding looks extremely uniform. How did you accomplish this with a cordless drill?

[Hdale85]

Hmm is this what many call a "plasma tweeter"?

[Amphiprion]

If you look at the bottom left, you will see a bolt sticking through the cap with a nut on it. I put the long end of the bolt in the chuck of a cordless drill (little 12V DeWalt) and squeezed until the whole assembly just barely moved (maybe 1 rotation every 2 seconds). I kept between 6" and 12" of wire length between my tension hand and the PVC pipe. The wire spool was on the floor and allowed to roll freely. There is a narrow range of angles at which, if you hold the wire under tension at relative to the position it is being wound on the coil, it will naturally 'roll' over itself and make the next turn. If you are to far away from that range, it starts coiling backwards over itself or if it is too far forward you start getting spaces. Trick is to have the wire continuously 'slip' over the last turn and form the next. I'm probably also lucky it turned out well.

Dougie,

This is the beginning of a REALLY REALLY BIG plasma tweeter Dual Resonant Solid State Tesla Coils (DRSSTC) are the latest and greatest things out there. Here is a picture from a company called Eastern Voltage Research that publishes texts and makes kits available for them:

http://www.easternvoltageresearch.com/images/minibrutecover01lg.jpg

[wigginjs]

Ohh... I'm seriously intrigued =). Are you building a kit using the boards available from that company? Do they have a complete kit with instructions or do they simply provide different boards that are needed?

[Amphiprion]

They sell a book which completely details the design, and they sell the boards. But you have to order the parts on your own. I am going to study the design, but I'm not sure if I'll order the boards. I have all the stuff (PCB software etc) to design my own stuff, and it's more fun that way.