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Old 4th March 2007, 11:51 AM   #1
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Default Class d elevatet top end

I am using a T-amp on my 3 ohms ribbons. With this amp i get a rising top end, with normal amps they meausure ruler flat.Is it possibel the caculate the filter on class d amps, so it fits the impedans on the speakers.
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Old 4th March 2007, 12:29 PM   #2
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This is how it meausure with class A-B amp.
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Old 4th March 2007, 02:20 PM   #3
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Yes, it is possible. I suggest having a look at the datasheet for the chip that's in your amp, or the sheet for the amp itself, to see what sort of filter you've got. Once you've got the filter type and component values, the calculations themselves aren't too hard.
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Old 4th March 2007, 02:26 PM   #4
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I am yoursing a T-amp now. but i am making amp 9 from 41hz. What values do i need, the impedans of the speakers is 3 ohm.
Sorry for my english.

André
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Old 4th March 2007, 03:40 PM   #5
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The rising top end may be due to an inductive impedance component of the ribbons interacting with the output filter of the amplifier. Try to flatten it with a RC series network at the output of the class D amplifier, with R in the range of 3 ohms and C in the range of 5uF. Most class-D designs expect a purely resistive load in the upper two octaves.
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Old 4th March 2007, 08:36 PM   #6
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maybe your right Eva. this is the impedans of the ribbon.Click the image to open in full size.
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