lm1875 fizzing away probelm - Page 7

blu_glo · 9th January 2013, 06:57 AM

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!!

PetruV · 9th January 2013, 07:16 AM

I had found a radio,just need to find batteries for it

PetruV · 9th January 2013, 11:19 AM

I dosent work but i think itsbthe radio

PetruV · 9th January 2013, 02:55 PM

An
STK412-170 would seem awesome,anyone can please post an schematic with layout and most importantly,are they good?!

PetruV · 9th January 2013, 07:16 PM

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

blu_glo · 10th January 2013, 07:40 AM

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

blu_glo · 10th January 2013, 07:45 AM

Quote:

Originally Posted by PetruV

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!

PetruV · 10th January 2013, 07:46 AM

Quote:

Originally Posted by blu_glo

That will need a serious heatsink to realise it's potential!

I know

PetruV · 10th January 2013, 10:29 AM

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

blu_glo · 10th January 2013, 10:47 AM

Quote:

Originally Posted by PetruV

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?

View Poll Results: Was a good idea to use two lm1875 or a big stk chip
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9th January 2013, 07:16 AM	#62
PetruV diyAudio Member Join Date: Dec 2012 Location: Bucuresti	I had found a radio,just need to find batteries for it

9th January 2013, 11:19 AM	#63
PetruV diyAudio Member Join Date: Dec 2012 Location: Bucuresti	I dosent work but i think itsbthe radio

9th January 2013, 02:55 PM	#64
PetruV diyAudio Member Join Date: Dec 2012 Location: Bucuresti	An STK412-170 would seem awesome,anyone can please post an schematic with layout and most importantly,are they good?!

10th January 2013, 07:40 AM	#66
blu_glo diyAudio Member Join Date: Aug 2005 Location: London, England	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