First attempt to build a Power amp!

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Maybe you should try posting this kinda stuff in the SMPSU section...I dun really like to deal with them...and I haven built or tried one yet...so before I continue...get your PSU up and running good first...I also see that you like to post in the SwitchMode Group...(yahoo)...I currently have an account there...perhaps you can post and get answers there..while I chip in to help a bit...most importantly ...get the PSU section up and running...an Amp without a PSU is like a car without an engine...
 
I would think ur amp is ok...but the PSU section is broken from the pics you posted..perhaps you can post some pictures of ur SMPSU...or izzit on another thread?? Maybe you can get a cheap0 4A 2x 30VAC Trafo...doesn't have to be really good...rig up a simple PSU...with some caps and a rectifier...then test away...once the power amp section is ok...proceed to fixing ur SMPSU...I think the schematic on Rod's site..at
http://sound.westhost.com/project89.htm
is really good...I haven tried it personally...but I do know a few people here have...so give it a shot...you might want to use parts from ur previous SMPSU...
 
I guess so...and the SG3525 can be "purchased" for free...check it out at
http://www.onsemi.com/site/products/summary/0,4450,SG3525A,00.html
Click on the samples button...fill in the necessary details registeration form etc...you get 20 for free...hehehe...you are probably wondering why I didn't tell you earlier...you do have to wait for the chip to arrive at your doorstep though...
 
Originally posted by MaXiZ
At http://www.ampslab.com/ia502schema.htm is reported to use the 142/147 and u say to don't use them.. why?

Look closely at the output section. Your schematic does not drive power darlingtons.

And i saw "input sensitivity 1v".. This mean that if my car stereo give and output of 30mV@360mA i can't hear nothing. Right?

This chip is not meant for cars.
 
Originally posted by li_gangyi

Read the posts carefully...

It would be wise of you to read my post carefully too.

Would you explain to me where the power darlingtons are?
 

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You will find that on page 6 of the application notes is "Figure 1 - Application Circuit with Power Darlingtons" whereas on page 9 is "Application Circuit using Power Transistors".

Please note that these 2 circuits are not the same.

Page 6 uses Darlington Outputs (TIP147/142) for Q1, Q2, Q3, Q4.

Page 9 circuit use drivers Q1, Q2 to drive output transistors BD912/911 which are configured as a Sziklai Compound Pair.
 
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