Class D amp Working

sonu · 5th July 2004, 04:57 PM

Now I have my Class D Amp ready. And it is a wooopping 650W of real power to drive my 2 HUNGRY Little Subs @ 2Ohms Load. I have powered it at 70V driving P150N Mosfets, and the amp is quite cool even at high power levels. As I have used it for my subs, I have used a active Linkwitz crossover, and it has a real base.
I have'nt used any feedback but have made short circuit & Overload circuit which works perfect.
There is only one problem that i have there is a 150Kz sine wave of 3V PP showing on my oscilloscope on the output, with no input to the amp, is it due to the dead time between the pulses.
I have used a Filter inductor of 550uH with .68uf Caps, which is not a perfect calculation.
Can anybody guide me to get a spread sheet for filter Calculation.

Regards,
Sonu.

selfservice · 5th July 2004, 05:26 PM

schematics please!!!!!!!!!!!!!!

sorinsistem · 3rd August 2004, 10:23 PM

schematics please!!!!

phase_accurate · 4th August 2004, 06:50 AM

Quote:

There is only one problem that i have there is a 150Kz sine wave of 3V PP showing on my oscilloscope on the output, with no input to the amp, is it due to the dead time between the pulses.

Isn't this simply the residual of the switching frequency ? In this case I wouldn't care about it for sub use unless you use very long cables (and you might therefore be a source of RFI).

Regards

Charles

sonu · 5th August 2004, 02:13 PM

It was a problem with LC Filter, now it is solved,
I have also made 1500W RMS Amp to 2 Ohms Load working Perfectly OK, little heating in the Inductors.

Only thing i am concerned is still i have to perfectly design the LC Filter. I am not getting proper info on Butterworth Filter design.

Regards,
Sonu.

phase_accurate · 5th August 2004, 02:35 PM

Quote:

Only thing i am concerned is still i have to perfectly design the LC Filter. I am not getting proper info on Butterworth Filter design.

What do you mean by "perfectly" ?

Do you want to get rid of ALL the ripple ?

If so, I wouldn't recommend doing it ! While it was always recommended to suppress the carrier as much as possible in older texts, there is now a general agreement that you sacrifice less audio quality when using less steeper filters with higher cutoff frequencies.

Regards

Charles

palesha · 5th August 2004, 06:14 PM

Congrates Sonu.
Changla vatla. Aaplya manasani ase kahi keleki khup changla vatatay. Mu punyacha aahe. He lok swatala khup shani samajtat. Software nanter electronics madhe aaplya lokani ase kahi keleki khup bare vaatle. Dhanyavad,
Mahendra Palesha

sonu · 13th August 2004, 04:10 PM

Hi palesha,
mi pan punecha,
where do u stay in pune, any contact no. n what do you do, Sorry to reply late, I am not a regular user of net.

Regards,
Sonu

palesha · 13th August 2004, 04:56 PM

Dear Sonu,
I hv TV antenna booster factory in Pune. U can call me on 26355702. I am in Bhawani Peth, Pune. What about u?
Mahendra Palesha

soundNERD · 14th August 2004, 03:49 AM

sonu, we'd still like to see a schematic and pcb...

thanks

5th July 2004, 04:57 PM	#1
sonu diyAudio Member Join Date: Apr 2004 Location: maharashtra	Class D amp Working Now I have my Class D Amp ready. And it is a wooopping 650W of real power to drive my 2 HUNGRY Little Subs @ 2Ohms Load. I have powered it at 70V driving P150N Mosfets, and the amp is quite cool even at high power levels. As I have used it for my subs, I have used a active Linkwitz crossover, and it has a real base. I have'nt used any feedback but have made short circuit & Overload circuit which works perfect. There is only one problem that i have there is a 150Kz sine wave of 3V PP showing on my oscilloscope on the output, with no input to the amp, is it due to the dead time between the pulses. I have used a Filter inductor of 550uH with .68uf Caps, which is not a perfect calculation. Can anybody guide me to get a spread sheet for filter Calculation. Regards, Sonu.

3rd August 2004, 10:23 PM	#3
sorinsistem diyAudio Member Join Date: Jan 2004 Location: Romania	schematics please!!!! __________________ PERFECT SOUND

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5th July 2004, 05:26 PM	#2
selfservice diyAudio Member Join Date: Jul 2004 Location: italy	schematics please!!!!!!!!!!!!!!

5th August 2004, 02:13 PM	#5
sonu diyAudio Member Join Date: Apr 2004 Location: maharashtra	It was a problem with LC Filter, now it is solved, I have also made 1500W RMS Amp to 2 Ohms Load working Perfectly OK, little heating in the Inductors. Only thing i am concerned is still i have to perfectly design the LC Filter. I am not getting proper info on Butterworth Filter design. Regards, Sonu.

5th August 2004, 06:14 PM	#7
palesha diyAudio Member Join Date: Nov 2001 Location: Pune India	Congrates Sonu. Changla vatla. Aaplya manasani ase kahi keleki khup changla vatatay. Mu punyacha aahe. He lok swatala khup shani samajtat. Software nanter electronics madhe aaplya lokani ase kahi keleki khup bare vaatle. Dhanyavad, Mahendra Palesha

13th August 2004, 04:10 PM	#8
sonu diyAudio Member Join Date: Apr 2004 Location: maharashtra	Hi palesha, mi pan punecha, where do u stay in pune, any contact no. n what do you do, Sorry to reply late, I am not a regular user of net. Regards, Sonu

13th August 2004, 04:56 PM	#9
palesha diyAudio Member Join Date: Nov 2001 Location: Pune India	Dear Sonu, I hv TV antenna booster factory in Pune. U can call me on 26355702. I am in Bhawani Peth, Pune. What about u? Mahendra Palesha

14th August 2004, 03:49 AM	#10
soundNERD diyAudio Member Join Date: Sep 2003 Location: Illinois	sonu, we'd still like to see a schematic and pcb... thanks