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Old 29th March 2008, 04:11 AM   #11
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Wouldn't type 12 be at the other end of the spectrum, i.e. too high frequency(20-200mhz)? They would also require almost twice as many turns as type 2.
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Old 29th March 2008, 04:28 AM   #12
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Quote:
Originally posted by theAnonymous1
Wouldn't type 12 be at the other end of the spectrum, i.e. too high frequency(20-200mhz)? They would also require almost twice as many turns as type 2.
I think that is right, that is why I did not use them, I really should \order the correct cores.
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Old 29th March 2008, 07:33 AM   #13
Pafi is offline Pafi  Hungary
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Searching through my resistors I dont have any smaller ones for the gate
What about 0 ohm? :-) Or a diode parallelled with 30 ohm. You can try decreasing the voltage of gate driver also.
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Old 29th March 2008, 12:28 PM   #14
Gyula is offline Gyula  Hungary
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12 Ohm paralleled with 1n5819, driven by IR2110 would be correct, even without dead time. Is the deadtime 1.2 us now? I suggest you the antiparallel diode in order to avoid switch-on through the Miller-capacitance too.
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Old 29th March 2008, 10:15 PM   #15
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I found some old 10ohm 1/4 watt axial resistors and made them fit into the surface mount spots now there is zero heating. I upped the power supply to 19V with a 6ohm load and it is staying cool to the touch.
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Old 30th March 2008, 05:06 PM   #16
thefish is offline thefish  United States
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Well I have let it run for 6 hours with a 19V supply at 6 ohms and it is cool (only the inductors are a bit warm). It sounds nice as a sub amp, for mids and highs it is ok, no real hissing. Does not seem to cause any FM interference unless radio is within 2 inches (and parallel to the doughnut face) of the inductors. The output is not very nice looking on the scope 2V p-p noise on the signal.


Scope image at 5V/div with a 100hz test signal input into amp:
Click the image to open in full size.

I think changing the output inductors should clean this up. Thanks for the help everyone.
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Old 30th March 2008, 08:28 PM   #17
Pafi is offline Pafi  Hungary
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Output waveform is quite good, considering that there is no feedback! Residual is normal, you can leave it, but you have to change inductors in order of less heating (of inductor). Try Arnold MPP cores, or Micrometal -2, -14!

You're welcome!
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