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Completed Plasma Speaker / Tweeter

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Richard

Wed Mar 19 2008, 07:38PM

Registered Member #1211
Joined: Fri Jan 04 2008, 05:20AM
Location: England - UK
Posts: 19

Finally finished building this driver board to power a flyback, with custom made discharge reflector :)

You can see it in action, together with the prototype design & video HERE

EDY19

Wed Mar 19 2008, 07:43PM

Registered Member #105
Joined: Thu Feb 09 2006, 02:54PM
Location:
Posts: 408

That is a very nice project for such a new member!

Keep it up! I recently finished my VTTC plasma tweeter, and the sound quality is great, however i used a digital camera video recorder, so the sound is awful in the recording! In real life, it really does sound quite fantastic

Nice clean work, too

northern_lightning

Wed Mar 19 2008, 08:18PM

Registered Member #1348
Joined: Sat Feb 23 2008, 07:48PM
Location: Michigan's Upper Peninsula
Posts: 22

sounds and looks awesome!!

Ken M.

Wed Mar 19 2008, 08:33PM

Registered Member #618
Joined: Fri Mar 30 2007, 11:15PM
Location: Us-Great Lakes
Posts: 628

Indeed Nice work.

Mates

Thu Mar 20 2008, 01:45AM

Registered Member #1025
Joined: Sun Sep 23 2007, 02:53PM
Location: Czech Rep.
Posts: 566

Richard, this one of the best playing plasma devices I've ever seen! Great work!

I'm pretty surprise you can get that sound from a fly-back. I have a pile of questions if I may...

Is this a regular modern type TV or PC monitor fly-back?

What freq. do you operate it?

And (I'm almost afraid to ask) what about sharing the whole schematics with us?

Thanks,
Mates

Experimentonomen

Thu Mar 20 2008, 05:21AM

Registered Member #941
Joined: Sun Aug 05 2007, 05:09AM
Location: in a swedish junk pile
Posts: 431

I agree, i saw this vid this morning and finding you as a member here was a total suprise.

Im planning to build one as well with one of these, a TL494/SG3525 and some fets:

Richard

Thu Mar 20 2008, 05:28AM

Registered Member #1211
Joined: Fri Jan 04 2008, 05:20AM
Location: England - UK
Posts: 19

Thanks for the positive comments, it's good to know I'm going in the right direction !
The next logical next step has to be a stereo version. Should be a fun challenge :)

Decided to keep away from using dance/electronic/synth music to demo it, as this can hide a multitude of failings in the sound reproduction (distortion & poor frequency response etc). Perhaps some strong female vocals or classical piece ? - might make for some interesting listening.

@ Mates - There's nothing special about the design, but I did pay special attention to the decoupling of each stage, to prevent unwanted oscillations & noise. The PCB design took the longest - the reflector was made of scrap.

You don't want a thick, long, white-hot arc. This will look impresive, but brings lots of problems. Excessive power consumption, overheating windings, electrode damage, instabillity and RF noise.

The small DC flyback, is from a colour portable TV - the operating frequency is 110Khz

GeordieBoy

Thu Mar 20 2008, 07:03AM

Registered Member #1232
Joined: Wed Jan 16 2008, 04:53PM
Location: Doon tha Toon!
Posts: 841

Hi Richard,

Great project and a very nicely built prototype too.

Although I personally like the dance track version better!

...somehow a little distortion doesn't matter there

and it's cool watching the modulation on the scope

The best vocal track I found to play through my singing tesla coil was "Sailboat" by Katie Mellua. It has a very clear and sharp vocal line which is quite dynamic too. Or anything with acoustic piano will show up the distortion if you are wanting material for a harsh test.

I used Rapture by Iio originally, but there's a lof of corona hiss in my demo at 250kHz.

-Richie,
(Newcastle UK)

Dr. Dark Current

Thu Mar 20 2008, 07:26AM

Registered Member #152
Joined: Sun Feb 12 2006, 09:36AM
Location: Czech Rep.
Posts: 3038

omg HFsstc-freak, where did you get that monster flyback?

Dr. 2N3055

Thu Mar 20 2008, 07:38AM

Registered Member #952
Joined: Mon Aug 13 2007, 06:07AM
Location: Finland
Posts: 361

Yea, and the picture is a monster too. I thought the max picture width was 400, not 1400.

Steve Conner

Thu Mar 20 2008, 08:12AM

Joined: Fri Feb 03 2006, 04:52AM
Location: Glasgow, Scotland
Posts: 6156

It's 400 now

Experimentonomen

Thu Mar 20 2008, 09:16AM

Registered Member #941
Joined: Sun Aug 05 2007, 05:09AM
Location: in a swedish junk pile
Posts: 431

I got it off ebay, just like 7 modern ones, 7 identical ones.

Richard

Thu Mar 20 2008, 09:49AM

Registered Member #1211
Joined: Fri Jan 04 2008, 05:20AM
Location: England - UK
Posts: 19

Great looking flyback that !!! - I wish I could get my hands on one.

We have a problem here in the UK now, in that all domestic electrical waste (TV's microwaves & anything remotley useful to us), goes for recycling. At one time you could buy the odd TV/VCR for parts, from your local tip, but not anymore. It's all piled up & shipped away somewhere. Really frustrating when you see an old Philips G8 TV, that you know has a really good 30KV AC flyback in it...

Still, such is 'progress'

Thanks 4 the suggestion of Katie Melua - have to agree though Richie, a fast track IS more entertaining :)
I'll connect up the RGB LED sequencer later & try to post another video later today.

Uzzors2k

Thu Mar 20 2008, 12:50PM

Registered Member #95
Joined: Thu Feb 09 2006, 10:57AM
Location: Asker, Norway
Posts: 1298

Crystal clear sound! Did you use frequency or pulse-width modulation?

bob golding

Thu Mar 20 2008, 06:10PM

Registered Member #1084
Joined: Mon Oct 29 2007, 03:58PM
Location:
Posts: 28

hi richard,
yes the new WEE regs are a pain. i got about 80 microwaves and dismantled them before the new regs came in. didnt have enough room to do all the tv,s as well:-)) one way of getting useful parts is the freecycle network. if you join your local group and ask for old tv,s and microwaves you will get them,and they are free. nice project,been on my list for while but havent got around to it yet.

bob

Richard

Fri Mar 21 2008, 01:21PM

Registered Member #1211
Joined: Fri Jan 04 2008, 05:20AM
Location: England - UK
Posts: 19

Many thanks for the info on the freecycle network - nearest is Birmingham - just too far to make it worth while :(

Got another video uploaded HERE with the RGB LED backlighting/sequencer working.

Now considering trying to wind my own transformer to try & improve the top end frequency response.
It falls off at 12Khz on the scope - commercial ion plasma tweeters can acheive 50+kHz

@Uzzors : I'm using FM modulation in the videos shown, but the board can be configured for PWM as well.

Experimentonomen

Fri Mar 21 2008, 03:27PM

Registered Member #941
Joined: Sun Aug 05 2007, 05:09AM
Location: in a swedish junk pile
Posts: 431

That is due to the system beeing aircored and oscillating at several MHz. Ferrite cores are limited to around 100KHz.

Richard

Fri Mar 21 2008, 04:36PM

Registered Member #1211
Joined: Fri Jan 04 2008, 05:20AM
Location: England - UK
Posts: 19

Absolutley ! - I've found above 115kz (with the ferrite material flybacks use), the output drops suddenly.

The commercial units all use RF air-cored transformers and sizeable horns, to acheive a decent volume.

Perhaps an electrode-based disharge with an air-cored transformer might be the way forward ?

The large modulated TC's I've seen, do perform OK, but seem to produce a great deal of corona noise....

GeordieBoy

Tue Mar 25 2008, 08:31AM

Registered Member #1232
Joined: Wed Jan 16 2008, 04:53PM
Location: Doon tha Toon!
Posts: 841

> Got another video uploaded HERE with the RGB LED backlighting/sequencer working.

Wicked - Nice one! Haven't heard that tune in a while either!
Sarah Cracknall is a babe

-Richie,

Dr. Dark Current

Tue Mar 25 2008, 04:48PM

Registered Member #152
Joined: Sun Feb 12 2006, 09:36AM
Location: Czech Rep.
Posts: 3038

Richard wrote ...

@Uzzors : I'm using FM modulation in the videos shown, but the board can be configured for PWM as well.

Ok, so how is it done? Do you feed your input signal to the frequency timing resistor pin of the IC or where?

Oh, and one more question, is it push-pull or bridge drive?

lpfthings

Sat Apr 12 2008, 08:08AM

Registered Member #1361
Joined: Thu Feb 28 2008, 04:57AM
Location: Cairns, Australia
Posts: 305

Hey as some of your comments in the vid suggest, do you have a kit for sale? I'm mainly looking for a PCB. Nice work, pretty clear sound too, especially the highs!

Dr. SSTC

Tue Jun 17 2008, 01:58AM

Registered Member #1407
Joined: Fri Mar 21 2008, 02:09AM
Location:
Posts: 222

richard we just want the schematics so if you wouldnt mind just giving them to us

Reaching

Tue Jun 17 2008, 12:06PM

Registered Member #76
Joined: Thu Feb 09 2006, 04:04AM
Location: Hemer, Germany
Posts: 454

jovica93 wrote ...

richard we just want the schematics so if you wouldnt mind just giving them to us

lol. if you want something, just as a shematic, this way to ask is one of them who will never lead to success..

Dr. SSTC

Tue Jun 17 2008, 09:11PM

Registered Member #1407
Joined: Fri Mar 21 2008, 02:09AM
Location:
Posts: 222

well i dont know how to ask if i made something good i would share it with youse

teslacoolguy

Tue Jun 17 2008, 09:35PM

Registered Member #1107
Joined: Thu Nov 08 2007, 04:09PM
Location:
Posts: 792

If i were to ask for the schemattics i would say,"Hi. Would you mind sharing the schemattics with us because that is one of the coolest things i have seen in a long time." Be polite to people so other prople can be polite to you.

FastMHz

Wed Jun 18 2008, 04:19PM

Registered Member #179
Joined: Wed Feb 15 2006, 08:08PM
Location: Hagerstown, Maryland - Close to Prime Outlets
Posts: 287

This is quite impressive!! Awesome

...

Wed Jun 18 2008, 05:59PM

Registered Member #56
Joined: Wed Feb 08 2006, 11:02PM
Location: Southern Califorina, USA
Posts: 2339

Richard wrote ...

Absolutley ! - I've found above 115kz (with the ferrite material flybacks use), the output drops suddenly.

The commercial units all use RF air-cored transformers and sizeable horns, to acheive a decent volume.

Perhaps an electrode-based disharge with an air-cored transformer might be the way forward ?

The large modulated TC's I've seen, do perform OK, but seem to produce a great deal of corona noise....

the next step up this would be some type of air cored transformer (generally a Tesla coil running in quasi class E) running at 4+MHz At this point the arc becomes silent and very high frequencies can be produced

Dr. SSTC

Fri Jun 20 2008, 05:18PM

Registered Member #1407
Joined: Fri Mar 21 2008, 02:09AM
Location:
Posts: 222

...

wasnt the whole point of this to make a singing arc not a singing airdischarge

Dr. SSTC

Fri Jun 20 2008, 05:18PM

Registered Member #1407
Joined: Fri Mar 21 2008, 02:09AM
Location:
Posts: 222

...

wasnt the whole point of this to make a singing arc not a singing airdischarge

teslacoolguy

Fri Jun 20 2008, 11:35PM

Registered Member #1107
Joined: Thu Nov 08 2007, 04:09PM
Location:
Posts: 792

It is and it still will be. All they are saying is instead using a flyback transformer and have it arc from it's hv lead to it's ground lead you would have a air cored transformer arcing from it's top lead to it's bottom lead kind of like i bipolar coil.

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