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View Poll Results: Was a good idea to use two lm1875 or a big stk chip
Use stk 8 27.59%
use lm1875 21 72.41%
Voters: 29. You may not vote on this poll

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Old 9th January 2013, 06:57 AM   #61
blu_glo is offline blu_glo  England
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I would have thought an op-amp oscillator is easiest to get working, but if you insist, Rod Eliott has offered a four transistor AF oscillator design

Audio Test Oscillator

which looks very good (as are all his articles). A circuit can be done with only two transistors but the ones I've come across using google briefly appear to have some fundamental flaws. This is what happens when people rely on computer simulations too much and not the good old "solder-and-and-try-it-out" method!!
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Old 9th January 2013, 07:16 AM   #62
PetruV is offline PetruV  Romania
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I had found a radio,just need to find batteries for it
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Old 9th January 2013, 11:19 AM   #63
PetruV is offline PetruV  Romania
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I dosent work but i think itsbthe radio
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Old 9th January 2013, 02:55 PM   #64
PetruV is offline PetruV  Romania
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An
STK412-170 would seem awesome,anyone can please post an schematic with layout and most importantly,are they good?!
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Old 9th January 2013, 07:16 PM   #65
PetruV is offline PetruV  Romania
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im starting to do this design ,but how do i put this on veroboard,since the holes line up to the layout
please any replies
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Old 10th January 2013, 07:40 AM   #66
blu_glo is offline blu_glo  England
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I think you'll save yourself a lot of aggravation spending cash on a pair of unassembled printed circuit boards.
As I already said, LM1875 is directly interchangeable with TDA2030, 40, 50 types. I seen PCBs for around €10 or so!
You can then tweak components knowing the wiring's already done right for you!

TDA2030A Amplifier Amp board Components DIY kit BTL/OCL | eBay
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Old 10th January 2013, 07:45 AM   #67
blu_glo is offline blu_glo  England
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Quote:
Originally Posted by PetruV View Post
An
STK412-170 would seem awesome,anyone can please post an schematic with layout and most importantly,are they good?!
That will need a serious heatsink to realise it's potential!
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Old 10th January 2013, 07:46 AM   #68
PetruV is offline PetruV  Romania
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Quote:
Originally Posted by blu_glo View Post
That will need a serious heatsink to realise it's potential!
I know
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Old 10th January 2013, 10:29 AM   #69
PetruV is offline PetruV  Romania
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Using this schematic the speker goes up and there is a faint trumpet noise,while nothing is hooked up to the input ,may this be becaue i used 55k instead of 50k
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Old 10th January 2013, 10:47 AM   #70
blu_glo is offline blu_glo  England
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Quote:
Originally Posted by PetruV View Post
Using this schematic the speker goes up and there is a faint trumpet noise,while nothing is hooked up to the input ,may this be becaue i used 55k instead of 50k
55K instead of 50K is not a problem just changes gain slightly.
- what value is R3?
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