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Class D Switching Power Amplifiers and Power D/A conversion

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Old 11th August 2012, 02:11 AM   #201
CPX is offline CPX  Romania
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TargetAmplificadores please retest THD at 1W ,10W and 100W output power(0.5 A rms 1,5A rms and 5A rms).
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Old 11th August 2012, 10:12 AM   #202
stewin is offline stewin  Kenya
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Quote:
Originally Posted by TargetAmplificadores View Post
Hello people, okay? I just set up my prototype in a proto-board. As I said I used a complementary pair (irf640 and IRF9640), although I'm not using a source of + - 60, but one of + - 25.

I'm impressed great sound quality I got, and how friends asked you guys post here some parameters that you guys have questions. First notice that I use an oscilloscope for PC, what do not cease to be a great tool and it got the values ​​of the parameters.
Again, these are values ​​that got in my equipment, using sinusoidal signal generator with a frequency of 1khz:

Power Supply: + - 25VDC (50Vdc).
Power (rms): 112.5 @ 8ohms
Sensibility: 0.8 V
Freq range: 20 to 18khz.
input impedance: 47kohms.
output impedance: 4ohms.
THD @ 1kHz: 0.18%
THD + n @ 1khz: 30.4%



even more
thanks for the simulation GOD bless you a lot
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Old 11th August 2012, 11:21 AM   #203
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0.1% THD at 1kHz, eww thats awful, if it was at 20kHz, it'd be ok but this is just terrible.

At 20kHz the THD must be atleast 10% if not more, considering this thing only oscillates at a few hundred kilohertz.

I may experiment with this scheme, but if i do so, the last opamp in the chain will be replaced with a comparator to speed things up.

As fumac already discovered, a carrier of atleast 1MHz is required before class d even starts to get anywhere near fullrange use with any acceptable sound quality.
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Old 11th August 2012, 12:30 PM   #204
pergo is offline pergo  Italy
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try LT1359 instead of TL074
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Old 11th August 2012, 12:45 PM   #205
stewin is offline stewin  Kenya
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Quote:
Originally Posted by Tekko View Post
0.1% THD at 1kHz, eww thats awful, if it was at 20kHz, it'd be ok but this is just terrible.

At 20kHz the THD must be atleast 10% if not more, considering this thing only oscillates at a few hundred kilohertz.

I may experiment with this scheme, but if i do so, the last opamp in the chain will be replaced with a comparator to speed things up.

As fumac already discovered, a carrier of atleast 1MHz is required before class d even starts to get anywhere near fullrange use with any acceptable sound quality.
hi tekko long time my friend welcome back . this amp sounds nice in real life pls simulate again
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Old 11th August 2012, 12:56 PM   #206
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Default my own pcb

Quote:
Originally Posted by stewin View Post
stewin
Hi every body
this is my pcb
is this ok?
stewin
stewin class d.zip
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Old 11th August 2012, 01:47 PM   #207
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Quote:
Originally Posted by Tekko View Post
0.1% THD at 1kHz, eww thats awful, if it was at 20kHz, it'd be ok but this is just terrible.

At 20kHz the THD must be atleast 10% if not more, considering this thing only oscillates at a few hundred kilohertz.

I may experiment with this scheme, but if i do so, the last opamp in the chain will be replaced with a comparator to speed things up.

As fumac already discovered, a carrier of atleast 1MHz is required before class d even starts to get anywhere near fullrange use with any acceptable sound quality.

Professionals have seen class D digital amplifier Over 1K5 watts, which has thd 0.9. For me, thd not reaching more than 1% tot, can now be considered an optimal amplifier. Try to build this circuit tekko, you will see that it has excellent sound quality. By chance you're an audiophile professional? If it is not, please disregard this 0.1% thd.

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Old 11th August 2012, 01:57 PM   #208
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This is the pcb copper + soldering
Attached Images
File Type: jpg solder.jpg (284.7 KB, 648 views)
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Old 11th August 2012, 02:34 PM   #209
stewin is offline stewin  Kenya
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hi abarth pls follow up this link it is the same amp . maybe it will help .

diysmps

hi Hadighorbani pls post a pdf or a jpg . i file can't open your roject
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Old 11th August 2012, 02:54 PM   #210
CPX is offline CPX  Romania
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Quote:
Originally Posted by Tekko View Post
0.1% THD at 1kHz, eww thats awful, if it was at 20kHz, it'd be ok but this is just terrible.
At 20kHz the THD must be atleast 10% if not more, considering this thing only oscillates at a few hundred kilohertz.
We know notting abut the load currents..he has to retest the amplifier with various output currents as i said.
Thd will only increase from 0.2% to max 1% at 20 khz which are inaudible anyway.
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