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Old 5th June 2012, 09:32 AM   #11
diyAudio Member
Join Date: Jun 2010
Originally Posted by jaycee View Post
in theory. in practice a 2 ohm speaker would go lower than 2 ohms, and of course its inductive. I'd recommend at least 4-6 pairs of TO-3 case devices to cope.
my dear friend
i cant use TO3 case
i dont have spease for heatsinc for that.
just tip of TIP142 and similar.
sorry for my bad
i like class D amp
help me please.
sorry for my bad conditions.
sorry for my bad english
thanks to all
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Old 5th June 2012, 09:44 AM   #12
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Join Date: Jun 2010
Originally Posted by CBS240 View Post
Is this 100Wrms or 100Wpeak?

100Wpeak @ 2R is only 10Vrms and 5Arms. That can be done with one pair of output transistors as far as SOA goes. However, at least 3 pair will be needed for the required current gain since you have to assume the worst case situation would be 14Vp into 1R reactive. (also Hfe decreases as frequency increases) I do not know what components are available in Iran, but try to choose lower Vceo higher conductance devices where DC Hfe holds up to at least 7A or so. Because Vce is low, secondary breakdown shouldn't be a problem. 100Wrms @ 2R would require more pairs of BJTs to be safe into reactive loads and have the current gain required. Or you can go with mosfets, but for that conductance range you would be limited to vertical type fets, or use multiple pairs of laterals.

hi dear friend
my country have bad poletice condition with usa
like jery and tom
my piopels love iran and our government
i can by any thing from out of iran but it is important to be cheap
bjt is expencive in iran and i dont like that
i have +-30 volt DC
help to creat class D please.
sorry for my bad english
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Old 5th June 2012, 09:46 AM   #13
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Join Date: Jun 2010
i most creat this amp to my university project.
very sorry for my bad condition and my bad english
thanks to all
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Old 5th June 2012, 11:29 AM   #14
jaycee is offline jaycee  United Kingdom
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Join Date: Apr 2004
Location: Norwich, UK
class D requires very fast mosfets, and very specialised circuitry to work well. under the conditions you have listed, this is not going to be possible.
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Old 5th June 2012, 02:49 PM   #15
wg_ski is online now wg_ski  United States
diyAudio Member
Join Date: Oct 2007
At those low rail voltages, slower switching speed isn't the end of the world. And low on-resistance high current TO-220 Hexfets should be easy enough to find if you need less than 100V Vds. It won't be 98% efficient, but 80% would do with a small heat sink. Still better than class AB, even if the design is not optimum.

Start with the data sheets for Hexfet drivers from IR, and the like. They have tutorials and app notes on class D. It's almost impossibe to get something like this custom designed for you over the internet unless a generous member steps in and works with you for a couple of weeks/months straight. The likelihood of that happeing is small. Learning to use resources like vendor data sheets, and getting ides from existing deisgns and modifying them is part of what you should be learning for your "university project".
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Old 5th June 2012, 03:45 PM   #16
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andrewlebon's Avatar
Join Date: Feb 2008
maybe this can help you Hadighorbani the easiest dclass amp with easy to get parts
is the ULTRA SIMPLE CLASS D AMP in the dclass thread comes on first time cant
get simpler than this
warm regards
andrew lebon
"It's Better to try and fail than to never know and always wonder"
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Old 5th June 2012, 07:21 PM   #17
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Join Date: Jun 2010
thanks friends
i decide to do class D
this decide best reason to ...
mony not important to me if i can creat class D
how can i creat power for class D?
i must TRY
sorry for my bad
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Old 5th June 2012, 07:38 PM   #18
oiphy is offline oiphy  Norway
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Join Date: Sep 2011
Location: norway
1000W RMS, 8 Ohm, Stereo Class D Power Amplifier Kit! | eBay

why not buy something like this... maybe without the power supply, and build from there?
greetings from Norway

" If you're going throu hell, keep going"
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Old 6th June 2012, 08:30 AM   #19
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Join Date: Jan 2012
* What model are those Kenwood speakers?
* Are you using them in your car, or is it a home system?
* What kind of crossover are you using?
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Old 6th June 2012, 06:44 PM   #20
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Join Date: Jun 2010
Hi friends
my country is in bad poletic condition
our peopel can not buy any thing of usa or ebay
around 30 years
kenwood 2ohm 100w
in my home and my brother home
i dont have crossover
you give me that please
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