lm3886 and differant volumes

kanifee · 3rd July 2008, 07:21 AM

Finally got my lm3886 up and running after a very bumpy start, only thin now is im getting two differant volumes on each channel, i dont have a pot wired up just a power amp, ive had it wired to a couple of sources and no change. my right channal is conciderable louder than my left, ive gone through and checked all my wiring/solder joints and im using the same speaker on each channel aswell.

any ideas?

Puffin · 3rd July 2008, 07:31 AM

kanifee. Is this a kit amp i.e a PCB based or a point to point ?

Inverting or non-inverting ?

I had this problem (which I fixed) , but am having difficulty remembering what the problem was !

kanifee · 3rd July 2008, 07:36 AM

Hi ts a non inverting amp kit from chipamp.com.

I have however changed the cap for new ones as i blew two and couldnt find the same brand ones so i replaced with all new 100uf 50v suntan ones.

Puffin · 3rd July 2008, 07:41 AM

Mine was following the building of a point to point amp. I seem to remember that I had something tied to ground which was restricting the input signal. Have you checked that you have no solder joins.

How did you blow the caps ? Did you blow the caps on both boards or just one. If just one, is this the board that has the problem. Have you blown any tracks ?

kanifee · 3rd July 2008, 07:48 AM

replaced the board with a spare i had so shouldnt be an issue, ill go over it again to check for shorts, i did notice that the input only needs one ground from either input channal to get a signal though either channal which i though was strainge.

pacificblue · 3rd July 2008, 10:16 AM

Did you check the values of the gain setting resistors? Are the right values at the right places? And are they okay or may one of them have blown together with the caps?

Puffin · 3rd July 2008, 10:41 AM

pacificblue, kanifee says "replaced the board with a spare" but the resistors may be wrong. Good point.

kanifee · 3rd July 2008, 11:53 AM

ok got it all up and running, i have no idea what it was it ust all of a sudden come to life.
I do however have another problem now, connected to a source that has seperate grounds for each input the amp works fine however hooked to my pc through the headphone jack i can only get a single channel at a time, its as if the amp doesnt like the shared ground of the head phone jack!
Its its the same when i have the volume pot solderd in.

kanifee · 3rd July 2008, 12:40 PM

sorry i lied, problem is still there with the channal being alot louder than the other

Nuuk · 3rd July 2008, 01:02 PM

Quote:

ok got it all up and running, i have no idea what it was it ust all of a sudden come to life.

Quote:

sorry i lied, problem is still there with the channal being alot louder than the other

Sounds very likely that you have a bad solder joint somewhere!

3rd July 2008, 07:21 AM	#1
kanifee diyAudio Member Join Date: Apr 2008	lm3886 and differant volumes Finally got my lm3886 up and running after a very bumpy start, only thin now is im getting two differant volumes on each channel, i dont have a pot wired up just a power amp, ive had it wired to a couple of sources and no change. my right channal is conciderable louder than my left, ive gone through and checked all my wiring/solder joints and im using the same speaker on each channel aswell. any ideas?

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3rd July 2008, 07:31 AM	#2
Puffin diyAudio Member Join Date: Feb 2006 Location: U.K	kanifee. Is this a kit amp i.e a PCB based or a point to point ? Inverting or non-inverting ? I had this problem (which I fixed) , but am having difficulty remembering what the problem was !

3rd July 2008, 07:36 AM	#3
kanifee diyAudio Member Join Date: Apr 2008	Hi ts a non inverting amp kit from chipamp.com. I have however changed the cap for new ones as i blew two and couldnt find the same brand ones so i replaced with all new 100uf 50v suntan ones.

3rd July 2008, 07:41 AM	#4
Puffin diyAudio Member Join Date: Feb 2006 Location: U.K	Mine was following the building of a point to point amp. I seem to remember that I had something tied to ground which was restricting the input signal. Have you checked that you have no solder joins. How did you blow the caps ? Did you blow the caps on both boards or just one. If just one, is this the board that has the problem. Have you blown any tracks ?

3rd July 2008, 07:48 AM	#5
kanifee diyAudio Member Join Date: Apr 2008	replaced the board with a spare i had so shouldnt be an issue, ill go over it again to check for shorts, i did notice that the input only needs one ground from either input channal to get a signal though either channal which i though was strainge.

3rd July 2008, 10:16 AM	#6
pacificblue diyAudio Member Join Date: May 2008	Did you check the values of the gain setting resistors? Are the right values at the right places? And are they okay or may one of them have blown together with the caps?

3rd July 2008, 10:41 AM	#7
Puffin diyAudio Member Join Date: Feb 2006 Location: U.K	pacificblue, kanifee says "replaced the board with a spare" but the resistors may be wrong. Good point.

3rd July 2008, 11:53 AM	#8
kanifee diyAudio Member Join Date: Apr 2008	ok got it all up and running, i have no idea what it was it ust all of a sudden come to life. I do however have another problem now, connected to a source that has seperate grounds for each input the amp works fine however hooked to my pc through the headphone jack i can only get a single channel at a time, its as if the amp doesnt like the shared ground of the head phone jack! Its its the same when i have the volume pot solderd in.

3rd July 2008, 12:40 PM	#9
kanifee diyAudio Member Join Date: Apr 2008	sorry i lied, problem is still there with the channal being alot louder than the other