Tomtech:
  You'll notice that the bigger wattage bulbs on the Akula video are not fully lit, either. But, without using those bigger high wattage bulbs, the device will not self run, as it won't be able pull in any "extra" energy, and then just works like an low efficiency inverter, instead.  At least, that's what I think, and notice on my set up. That, there is an optimum load level, where the device works best.

I'm currently using the

hi Tomtech29,

Try not to use the varistor i have previously removed those as those were getting heated really bad,swelling up.
The varistor rating i was using 470volts high Amps rated.

Instead of 7.1 ohms i just sticking with 5.1ohms 2 watt resistor which is the same value resistor to mosfet drain.It would be better to place a 30volts sk diode in parallel with resistor 5.1ohms to drain.
This i have not implemented during PCB circuit designing.
3Amps 1000volts diodes UF5408 is used between drain source and another for snubber.

Akula was using 600volts IGBT but i am using 1200volts IGBT which did not fail even without snubber.But the waveform looks better with snubber circuit in place like i have attached few days back.

  Grum:
  That was the diagram that I further corrected. As the rectified 311 volts from the inverter goes to the 28 turns yoke coil, as can be seen in the video. Not to the center tap on the yoke. There is no earth ground shown on that diagram, either. And some other things as well.

  Magpwr:
  The red taped inductor was 12 turns, or (twice 12 turns, possibly bifilar). The yellow taped feed back loop is also about 12 turns. Both together make up 1/2 of the number of winding on the bigger output coil, which has 48 turns, if only a single layer was used. There are no exact turn counts that I know of.  These are my observations, and how I made my big air coils. You can compare them to what you see on the video.
  And there are no correct diagrams of that device, either.  All that have been made are wrong. And that is also why it looks more complicated in the diagram than can be seen on the video.
  We did a lot of close examination of that first self runner video, back then, but could not get it all figured out, as there were too many unknowns.
 I switched over to the second Akula device, when Ruslan came out with more information on how to replicate it.

  Geo was going to connect the TL494 driver board that he made as a replication of the first Akula device driver board, to the grenade/yoke set up. But, hasn't shown it if he did do it. So, I don't know what happened with that idea.
 

  Dog-One:
  quote:
  "I got to ask, do you all think there is some magic behind using the push-pull driver?
                                                                                                                   end quote.
   Yes, only because up to now all the higher powered FE generators use a push-pull configuration to create a strong Magnetic Pulse, that is superimposed by the HV HF pulse from one type of HV pulser driver circuit, or another. 

  I believe that the magnetic field from the induction circuit is the main factor in the effect. As high voltage by itself won't do much work.
   If you can create a strong magnetic field with the use of your audio amp, which should be able light several hundred watts worth of bulbs as a load, than I see no problem to superimpose it, rectify the output, and send it back to the input. Simple, right?

   Yes, only because up to now all the higher powered FE generators use a push-pull configuration to create a strong Magnetic Pulse, that is superimposed by the HV HF pulse from one type of HV pulser driver circuit, or another. 

  I believe that the magnetic field from the induction circuit is the main factor in the effect. As high voltage by itself won't do much work.
   If you can create a strong magnetic field with the use of your audio amp, which should be able light several hundred watts worth of bulbs as a load, than I see no problem to superimpose it, rectify the output, and send it back to the input. Simple, right?

My feeling about the push-pull driver is it's a commonly used power inverter type circuit.  Many DC to DC converters operate this way.  Also, with push-pull, you effectively double the input voltage to the primary.  This is all well and good as long as you plan on taking the output of the secondary and rectifying it, since you don't really care about the harmonics--they'll all go away once rectified and filtered.

For the Ruslan device, it would seem to me you actually want a clean sine wave, since what is going through the two coils (grenade and heater coil) is AC.  We've seen this on several Ruslan scope shots.  Personally, I think Ruslan went to a lot of trouble to make sure his push-pull driver and yoke would output a clean sine wave.  I went down this road and finding the proper combination of components is hard enough, but then you toss into the mix the push-pull has to run at a specific frequency makes things ten times more difficult to get the nice sine wave you're after.  Hence my decision to try something easier.  Enter the Class-D audio amplifier...

When I use this amplifier, getting a clean sine wave running at the frequency I want is nearly child's play.  And yes, it will make a screw driver almost glow if you insert it into the air core.  There is no difficulty in getting the capacitors tuned and lighting up several 100 watt light bulbs.  I still don't know yet if things will self-run this way or not, I'm about ten days out from having my new Tesla driver boards fabricated.  I modified the ones I have about as far as I could go and hit a wall getting them to where they need to be.  The new ones are simple and should do the job just fine.

I'm hoping someone might try testing an audio amp as I have done, so I have someone to compare notes with.  From what I have seen so far, this method is by far easier and gives very consistent results.  The only large change I had to make going this way is to switch to a 48 volt power supply because most Class-D amplifiers I have tried need at the very minimum 25 volts to operate.  With this voltage one has to be a little careful rectifying it down to 12 or 5 volt to run the other logic circuits.  I suppose you could use two power supplies though--a 48 volt for the amp and a lower voltage, lower power one for the other circuits.  Anyway, it's an option and I'd like to see someone give it a go and share their opinion.

Hi Dog,
So you reccon to use the amplifier?  I have at home similar to this one - http://www.ebay.ie/itm/200W-12V-Mini-Hi-Fi-Amplifier-Amp-Radio-MP3-Stereo-Car-Bike-home-/330748381081?hash=item4d0223c799.  Would it be OK to try it out?

My feeling about the push-pull driver is it's a commonly used power inverter type circuit.  Many DC to DC converters operate this way.  Also, with push-pull, you effectively double the input voltage to the primary.  This is all well and good as long as you plan on taking the output of the secondary and rectifying it, since you don't really care about the harmonics--they'll all go away once rectified and filtered.

For the Ruslan device, it would seem to me you actually want a clean sine wave, since what is going through the two coils (grenade and heater coil) is AC.  We've seen this on several Ruslan scope shots.  Personally, I think Ruslan went to a lot of trouble to make sure his push-pull driver and yoke would output a clean sine wave.  I went down this road and finding the proper combination of components is hard enough, but then you toss into the mix the push-pull has to run at a specific frequency makes things ten times more difficult to get the nice sine wave you're after.  Hence my decision to try something easier.  Enter the Class-D audio amplifier...

When I use this amplifier, getting a clean sine wave running at the frequency I want is nearly child's play.  And yes, it will make a screw driver almost glow if you insert it into the air core.  There is no difficulty in getting the capacitors tuned and lighting up several 100 watt light bulbs.  I still don't know yet if things will self-run this way or not, I'm about ten days out from having my new Tesla driver boards fabricated.  I modified the ones I have about as far as I could go and hit a wall getting them to where they need to be.  The new ones are simple and should do the job just fine.

I'm hoping someone might try testing an audio amp as I have done, so I have someone to compare notes with.  From what I have seen so far, this method is by far easier and gives very consistent results.  The only large change I had to make going this way is to switch to a 48 volt power supply because most Class-D amplifiers I have tried need at the very minimum 25 volts to operate.  With this voltage one has to be a little careful rectifying it down to 12 or 5 volt to run the other logic circuits.  I suppose you could use two power supplies though--a 48 volt for the amp and a lower voltage, lower power one for the other circuits.  Anyway, it's an option and I'd like to see someone give it a go and share their opinion.

hi Dog-One,

I would suggest not to waste time on audio amplifier with 2 simple reason
1)PWM Generator can easily do eg:1Khz to 1Mhz without changing any components.We are not into audio fidelity.

2)Duty cycle can be varied from 3% to 49% as an example for PWM which can still produce sine-wave across capacitor example after 3 turns.Varying PWM give us the full control to limit the current consumption as desired.Duty cycle control also effect amplitude of the sine-wave to a desirable level.

Nothing more to talk about regarding audio amps.