Bought a XY LM3886 Kit. - Page 40

johnny52 · 27th June 2012, 02:57 AM

Here is the picture. Sorry.

fab · 27th June 2012, 02:03 PM

Quote:

Originally Posted by johnny52

Here is the picture. Sorry.

Hi Johnny52

Your choice of implementation works (as in mine it does) but to be clear the best option is probably to cut the GND to really isolate the input/Feedback GND from the rest of the GND trace as pointed out earlier in the thread. Thus, this is the preferred option- if required:

Good luck

Fab

johnny52 · 29th June 2012, 02:12 AM

Quote:

Originally Posted by fab

Hi Johnny52

Your choice of implementation works (as in mine it does) but to be clear the best option is probably to cut the GND to really isolate the input/Feedback GND from the rest of the GND trace as pointed out earlier in the thread. Thus, this is the preferred option- if required:

Good luck

Fab

Same thing as post #38. I'll cut the traces.

I thought that 2R was on power supply ground instead of input signal ground. Sorry Fab.

fab · 29th June 2012, 10:55 PM

Quote:

Originally Posted by johnny52

Same thing as post #38. I'll cut the traces.

I thought that 2R was on power supply ground instead of input signal ground. Sorry Fab.

2R was on power supply ground of PCB (as a compromise) when not cutting the trace of input signal ground. Best way is as per post #38

Good luck

Aguilabrava · 29th June 2012, 11:17 PM

Hi Guys:

I'm really sorry I haven't been able to participate here for a while, I've been busy, as always, just to keep my head out of the water.

I haven't done anything yet, I still have the new PEMO PCB's intact, even though I already have all the components, but I'll be working on them soon.

I was talking to my nephew the other day, he wants to build a guitar amplifier, I suggested the idea of doing it with one LM3886 PCB, one transformer and one PSU, so we'll be talking about that soon.

I am very happy to see that many have benefited from this thread, again, the big thanks go to AndrewT, Pacificblue and all the others that have been so generous to share their knowledge, something that's just priceless.

I'll be back soon....

alexisk10 · 17th July 2012, 09:28 AM

I have a question, when i have not connect any input on my lm3886 amp (stereo) i'm getting 25V at the output and when i connect to the input an audio source i'm getting around 25mV without speakers connected

I have use the circuit in datasheet

This is normal?

pacificblue · 17th July 2012, 04:19 PM

Which of the circuits in the datasheet did you use?

And no, it is not normal. Check whether Rin is connected correctly.

alexisk10 · 17th July 2012, 04:45 PM

the following circuit without te potentiometer

AmadeusMozart · 25th July 2012, 10:21 AM

when no input is connected then without the potentiometer there is no return to ground so the voltage goes all over the place. If not using a potentiometer then replace it with a fixed value resistor to ground.

alexisk10 · 27th July 2012, 09:03 AM

In that circuit the ground point is common? The signal ground and the voltage ground is common?

17th July 2012, 04:19 PM	#397
pacificblue diyAudio Member Join Date: May 2008	Which of the circuits in the datasheet did you use? And no, it is not normal. Check whether Rin is connected correctly. __________________ If you've always done it like that, then it's probably wrong. (Henry Ford)

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27th June 2012, 02:57 AM	#391
johnny52 diyAudio Member Join Date: Jan 2008	Here is the picture. Sorry.

29th June 2012, 11:17 PM	#395
Aguilabrava diyAudio Member Join Date: Jan 2012	Hi Guys: I'm really sorry I haven't been able to participate here for a while, I've been busy, as always, just to keep my head out of the water. I haven't done anything yet, I still have the new PEMO PCB's intact, even though I already have all the components, but I'll be working on them soon. I was talking to my nephew the other day, he wants to build a guitar amplifier, I suggested the idea of doing it with one LM3886 PCB, one transformer and one PSU, so we'll be talking about that soon. I am very happy to see that many have benefited from this thread, again, the big thanks go to AndrewT, Pacificblue and all the others that have been so generous to share their knowledge, something that's just priceless. I'll be back soon....

17th July 2012, 09:28 AM	#396
alexisk10 diyAudio Member Join Date: Mar 2010	I have a question, when i have not connect any input on my lm3886 amp (stereo) i'm getting 25V at the output and when i connect to the input an audio source i'm getting around 25mV without speakers connected I have use the circuit in datasheet This is normal?

25th July 2012, 10:21 AM	#399
AmadeusMozart diyAudio Member Join Date: Oct 2009 Location: New Zealand	when no input is connected then without the potentiometer there is no return to ground so the voltage goes all over the place. If not using a potentiometer then replace it with a fixed value resistor to ground.

27th July 2012, 09:03 AM	#400
alexisk10 diyAudio Member Join Date: Mar 2010	In that circuit the ground point is common? The signal ground and the voltage ground is common?