FEELER: Plasma Speaker Kits

[Fiddy]

If you get your hum isolated, Id love to get a kit from ya, or at least a spike for another build. If i build a micro brute, would it be possible to change between a full spectrum driver for audio and DR driver for larger sparks and midi control, or do they require significantly different coil setups?

And side note:
Do you live in oz? Aren't laser pointers outlawed there or is that a rumor?

Hey,

Are you sure? the thing still plays audio but the main heatsink gets hott fairly quickly, ive sent a kit to Things to help figure out what is causing the problem.

I imagine going from a large spark midi controller (Xenosonic modulator for the microbrute) to a full spectrum plasma speaker will need lots of modification, the Microbrte runs at ~300khz but most plasma speakers are running at 1-4Mhz.

Yes laser pointers are restricted to 1mW, but ive blown that out of the water

 

[Sigurthr]

Yeah you could run an array of relays and switches to "switch out" the tank capacitor, switch feedback method, and switch the modulator/interruptor back and forth from midi input/pwm to cw. Lots of work for no real reason other than I guess to have a "do it all" coil. The more complexities you add to a coil system the more headaches it brings though. You would pretty much instantly blow your bridge if you had the tank cap IN circuit while either the feedback or interruptor is set to "sstc", so kinda risky.

SSTCs are fairly easy to build, driver wise. I've put one together on copper padded perfboard in under two hours from scratch and memory alone. Most of that time is simply soldering time to make the large low inductance solder-bridge "traces".

Btw, Fiddy, plasma speakers can operate just fine as low as 25KHz. The arc just gets a bit quieter above 1MHz and such a high f0 allows for a very small secondary. One of the heavy weight coilers built a 75KHz f0 VTTC which uses high level plate modulation from a 5kVA modulation transformer; crystal clear sound that shakes the walls. Over 4kWPEP output power on peaks.

 

[DashApple]

ill second the audio SSTC at low Frezez , i got great results with a 230 Khz SSTC running from smoothed 230 V DC , arc was practicaly silent , apart from the audio it was playing

 

[Things]

Hey mate, think you're gonna like this

Still got the protective tape on until I figure out vent hole placement, but I think it looks pretty sexy. Might as well do something productive while I wait for my scope to get back

 

[Fiddy]

Holy fricken jeezus you work fast!

That looks really nice great job

 

[Things]

Couple more pix, just finished the back panel

Engraving on the opposite side of the acrylic that you view from looks a heap better IMO, gives an awesome 3D look, and you don't notice the scan lines as much

 

[Fiddy]

you sir have outdone yourself ;D

 

[Things]

Haha

'Scuse the taped up primary and secondary

Hoping the fan there will be enough for the heatsink, we shall see

 

[Pilgor]

WOW!!! That is really professional looking. Really clean. Great work.

 

[Things]

Thanks, took quite a bit of trial and error to get the casing right.

Also when I first put it together in the case, it wouldn't work properly, no breakout at all. Found out that you need to keep the primary wires away from the antenna apparently!

I need a wider range of various gas-filled tubes to play with

 

[Sigurthr]

Really awesome job, Things!!! I wish I could construct cases, it makes a huge difference in the presentation of the coil.

I know where you can get top notch electrodeless discharge tubes of many rare gasses and mixes, but they are not cheap! Typically run $100ea. I struck a deal and got my 3 for only $270.

 

[Things]

Cheers Now just gotta try figure out this bloody annoying buzz Fiddy has been talking about. I made a brief video of it here:

 

[Things]

Managed to get this pic before it completely messed up my SD card

Managed to get the SD card back by trying to format it a few times, eventually it worked:

This thing gives off some _nasty_ RF

 

[Sigurthr]

Just saw the video, when I read "buzz" I was thinking of a low frequency tone! That is clearly a "whine". It sounds like the residual square wave amplitude modulation left over from the PWM carrier frequency. The only way to get rid of it is to redesign the circuit to increase the PWM carrier frequency.

 

[Meatball]

So why would the buzz fail to appear in his prototype? I didn't see anything about the design being changed since then.

 

[Fiddy]

these are the prototypes