My very first Class D pwm (switching) amplifier. - Page 59 - diyAudio
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Class D Switching Power Amplifiers and Power D/A conversion

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Old 15th March 2006, 07:44 PM   #581
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I'm sorry but what's the problem? I mean, what do you expect it to sound like when it clips? I'd say a good crackle is normal. Add clip protection or don't drive it that hard? If it comes out of clipping OK and survives I'd say good job.
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Old 15th March 2006, 09:07 PM   #582
fehrudi is offline fehrudi  Hungary
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Thanks for suggestion Pierre!

I think I found the problem.

The others side of 10k resistor (R7) on the SD pin is connencted to the COM pin on the PCB.
Later I removed that resistor and connected it directly. But that was wrong, because the SD pin is referred to the Vss.
So, when I shorted the resistor (R3) between Vss and COM, that crackle disappeared.

That crackle before was not normal. Lets say, that was something like blatter.

I only wanted it to crackle like a class AB amp (or at least similar to it).
I dont want to add clip protection unless I have to.
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Old 16th March 2006, 07:27 AM   #583
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Has there been any results on this from IR

Seems to run at a high frequency, self oscillation, not sure on how its done.


http://www.irf.com/technical-info/re.../iraudamp1.pdf
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Old 16th January 2007, 02:16 PM   #584
mrx23 is offline mrx23  Hungary
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Here you can find designing of a BCA amp with schematics:
it has NO dead time!-> minimal THD
http://www.diyaudio.com/forums/show...&threadid=94263
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Old 16th January 2007, 02:25 PM   #585
lkadar is offline lkadar  Hungary
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The correct link is: Redesign Crown K2/1 BCA amplifier (with schematic) pls help with the feedback
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Old 16th January 2007, 02:41 PM   #586
Pierre is offline Pierre  France
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mrx23,
Are you going to post the BCA schematics in EVERY thread in this forum?
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Old 16th January 2007, 02:52 PM   #587
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I am not that sure if the statement of BCA having no deadtime really holds¨!

Regards

Charles
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Old 16th January 2007, 06:04 PM   #588
rogs is offline rogs  United Kingdom
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It has always intrigued me why the designers of these amps choose such ridiculous values for some of the components -- on the 'main' pcb R246 is shown as a variable 10K resistor - and R245 is shown as 5.11K in series with it.

5.11K in series with a variable resistor!

I wonder how much else doesn't actually need to be there
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Old 16th January 2007, 07:06 PM   #589
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One reason the 5.11k could be chosen because the lower tolerance may also have better temperature stability.
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Old 17th January 2007, 07:19 AM   #590
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Quote:
It has always intrigued me why the designers of these amps choose such ridiculous values for some of the components -- on the 'main' pcb R246 is shown as a variable 10K resistor - and R245 is shown as 5.11K in series with it.
Are you wondering why there is a series resistor or why it is 5.11k ? There is a logical explanation for both of course. But before I give you the answer I let you think a little more !!

Regards

Charles
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