lm1875 fizzing away probelm - Page 4

PetruV · 7th January 2013, 09:55 PM

Signal ground is not conected to power ground and standby pin is conected to positive,while writing this,i realized!maybe 5v is not enough to get it out of standbyD:

PetruV · 7th January 2013, 10:03 PM

Yep just checked the datasheet and the switch on curent for standby is 8.5v
Now need a circuit that can get me 12v from 5v but not drawn too much current to damage a laptop

PetruV · 8th January 2013, 08:38 AM

would a 55w lightbulb work

PetruV · 8th January 2013, 08:50 AM

Just found an 21w lightbulb

picowallspeaker · 8th January 2013, 08:54 AM

Hey, I like the way you take possession of your thread!
I would say : keep the audio things separate from the computer thing!
Or you risk to break both! But the main matter is the power supply: it's much
better in having a linear supply - noiseless and powerful- such a transformer-bridge-reservoir/smoothing capacitors. For USB powered amplifiers, I would
stick to amplifiers based on chips housed in 8 pin-dual in line which may absorb
no more than 1 W. Also find some 4 Ω( or 3.2 Ω ) speakers that may enhance
sinergy between a low voltage supply amplifier and speakers.

OMG! Sinergy !!!

superR · 8th January 2013, 09:53 AM

Maybe this is a better option for a first project;
LM1875 GC Circuit Audio Amplifier Board Kit | eBay

PetruV · 8th January 2013, 10:06 AM

Now testing it with the sinal round hooked up to power ground,i only very distorted audio from just one chanell,why? please answer

PetruV · 10:30 AM

Quote:

Originally Posted by picowallspeaker

Hey, I like the way you take possession of your thread!
I would say : keep the audio things separate from the computer thing!
Or you risk to break both! But the main matter is the power supply: it's much
better in having a linear supply - noiseless and powerful- such a transformer-bridge-reservoir/smoothing capacitors. For USB powered amplifiers, I would
stick to amplifiers based on chips housed in 8 pin-dual in line which may absorb
no more than 1 W. Also find some 4 Ω( or 3.2 Ω ) speakers that may enhance
sinergy between a low voltage supply amplifier and speakers.

OMG! Sinergy !!!

This powesuplly is very good and sounds better than some linear supplies.The transformers are very expensive and big and offer not much benefit,Yes im realy afraid of breaking my gaming laptop so any of you can come up with a simple tone generator?
All my spekers are 4 ohms,3.2 ohms are those little crap speakers that i blow up from the moment i see

PetruV · 8th January 2013, 10:11 AM

I have aleardy used tda 2003 kit in my usb amp and tda 8560 or something like that in my main amp

picowallspeaker · 8th January 2013, 11:02 AM

55 and 21 W don't exist as values for 'old type' lightbulbs
I know 25 and 60 W ratings ! So, are you sure that you are referring to
the classic lightbulbs, and not the electronic ones ?
Same for the power supply

RE: I blew those crappy speakers from the moment I see

View Poll Results: Was a good idea to use two lm1875 or a big stk chip
Use stk	8	32.00%
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7th January 2013, 09:55 PM	#31
PetruV diyAudio Member Join Date: Dec 2012 Location: Bucuresti	Signal ground is not conected to power ground and standby pin is conected to positive,while writing this,i realized!maybe 5v is not enough to get it out of standbyD:

7th January 2013, 10:03 PM	#32
PetruV diyAudio Member Join Date: Dec 2012 Location: Bucuresti	Yep just checked the datasheet and the switch on curent for standby is 8.5v Now need a circuit that can get me 12v from 5v but not drawn too much current to damage a laptop

8th January 2013, 08:38 AM	#33
PetruV diyAudio Member Join Date: Dec 2012 Location: Bucuresti	would a 55w lightbulb work

8th January 2013, 08:50 AM	#34
PetruV diyAudio Member Join Date: Dec 2012 Location: Bucuresti	Just found an 21w lightbulb

8th January 2013, 08:54 AM	#35
picowallspeaker diyAudio Member Join Date: Apr 2007	Hey, I like the way you take possession of your thread! I would say : keep the audio things separate from the computer thing! Or you risk to break both! But the main matter is the power supply: it's much better in having a linear supply - noiseless and powerful- such a transformer-bridge-reservoir/smoothing capacitors. For USB powered amplifiers, I would stick to amplifiers based on chips housed in 8 pin-dual in line which may absorb no more than 1 W. Also find some 4 Ω( or 3.2 Ω ) speakers that may enhance sinergy between a low voltage supply amplifier and speakers. OMG! Sinergy !!!

8th January 2013, 09:53 AM	#36
superR diyAudio Member Join Date: Nov 2006	Maybe this is a better option for a first project; LM1875 GC Circuit Audio Amplifier Board Kit \| eBay

8th January 2013, 10:06 AM	#37
PetruV diyAudio Member Join Date: Dec 2012 Location: Bucuresti	Now testing it with the sinal round hooked up to power ground,i only very distorted audio from just one chanell,why? please answer

8th January 2013, 10:11 AM	#39
PetruV diyAudio Member Join Date: Dec 2012 Location: Bucuresti	I have aleardy used tda 2003 kit in my usb amp and tda 8560 or something like that in my main amp

8th January 2013, 11:02 AM	#40
picowallspeaker diyAudio Member Join Date: Apr 2007	55 and 21 W don't exist as values for 'old type' lightbulbs I know 25 and 60 W ratings ! So, are you sure that you are referring to the classic lightbulbs, and not the electronic ones ? Same for the power supply RE: I blew those crappy speakers from the moment I see