4000 watt Audio Amp to drive Tesla coil (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

---------- Forwarded message ----------
Date: Mon, 10 Sep 2007 10:57:28 -0700 (PDT)
From: Timka <tomasdoc2002@xxxxxxxxx>
To: tesla@xxxxxxxxxx
Subject: 4000 watt Audio Amp to drive Tesla coil

Hello all,
   
  Did anyone ever used and audio amp to drive Tesla coil before?
   
  I came across a few mosfet amps on EBay, new but relatively cheap. The one I was looking at is rated at 4000 watts bridged output into 4 Ohms load. Now, I figured if I would use copper tubing, the resistance wouldn’t be a major factor after all.
   
  Another good thing is that I can feed anything into it via signal generator or even audio to see how coil behaves.
   
  Now, nasty things that I worry about:
   
  1) It would really suck if I ended up blowing final mosfets due to TC secondary kick back and frying internal circuitry, which would be a total fiasco and probably would puzzle a lot of clerks at the return department. Ad states that amp employs overload protection but whoever designed them back in China never envisioned a million volts kickback from an ordinary speaker, so I'm not holding my breath there. Any suggestions here?
   
  2) What kind of power supply is needed? In a car amp works off alternator and use around...... around a lot of amps! In fact, not every alternator can pull a 4000 watts amp as the most of them is in the area of 120 amps on average. Here is quick math for 4K watts amplifier:
   
  1 channel with 4000 watts RMS per channel doubled to the account for amplifier inefficiency (4000 watts X 2 = 8000 watts), then divided by the average output Voltage of an alternator, 13.8 volts (8000 divided by 13.8 = 580 amps). Since the average signal requires about 1/3rd of the average power in a tone used to drive TC, dividing by 3 (580 amps divided by 3 = 193 amps). This is the result of the amplifier's approximate average current draw.
   
  Soooooooo, how and where in the world do I get a source of 200 constant amps at 13.8 volts? This is not your average power supply you can plug into a wall. I was thinking of getting a car booster/starter a.k.a battery charger, it's the size of small fridge, with 2 fat clammed cables, weights about 60lb and probably employs a very large transformer you can use to kill your mother in-law that can be plugged into a wall. Another ad claims that this car starter can give an instant 300 amps surge or so but how about using it for longer than instant or lets say 10 min? Can it pull this amp? Of course I can add a few 2 farad audio caps in between, but would it be enough?
   
  The specks of amp are as follows:
   
  Frequency Response: 15Hz- 35kHz (not too great but hey, it's audio)
   
  It's on ebay listed under the folowing #150156590184
   
  All suggestions are welcome,
   
  Thanks in advance,
   
  Tim
   
   
   
   
   

       
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