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Old 27th June 2012, 02:57 AM   #391
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Here is the picture. Sorry.

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Old 27th June 2012, 02:03 PM   #392
fab is offline fab  Canada
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Originally Posted by johnny52 View Post
Here is the picture. Sorry.

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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
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Old 29th June 2012, 02:12 AM   #393
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Originally Posted by fab View Post
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.
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Old 29th June 2012, 10:55 PM   #394
fab is offline fab  Canada
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Originally Posted by johnny52 View Post
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
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Old 29th June 2012, 11:17 PM   #395
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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....
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Old 17th July 2012, 09:28 AM   #396
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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?
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Old 17th July 2012, 04:19 PM   #397
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Which of the circuits in the datasheet did you use?

And no, it is not normal. Check whether Rin is connected correctly.
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Old 17th July 2012, 04:45 PM   #398
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the following circuit without te potentiometer
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Old 25th July 2012, 10:21 AM   #399
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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.
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Old 27th July 2012, 09:03 AM   #400
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In that circuit the ground point is common? The signal ground and the voltage ground is common?
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