4 Pin Amp output to 3 Pin headphone jack?

Nukeb32dc2 · 02-16-2009, 06:31 PM

So this one is stumping me and I am wondering if any of the smarties on this forum can help:

I have a four pin amplified audio output on a prototype motherboard and I am looking to convert this to a 3 pin output so I can then attenuate and use standard headphones.

The one caveat is that the amplifier is push/pull. Therefore, there are no grounds- AC is fed to each speaker as the polarities have opposite sin waves. I understand they make 4 pin headphones but this will not suffice. Using one channels ground will not work either as it sounds quite distorted.

Is this possible?

If anyone can point me in the direction of a component or circuit that would do this I would be SO greatful! It seems simple but in reality....its over my head!

Rob Withey · 02-16-2009, 06:33 PM

This is exactly what a ground loop isolator does - it isolates the grounds.

Nukeb32dc2 · 02-16-2009, 06:47 PM

Thanks but I am not looking to insulate grounds; I am looking to create a common ground and 2 positives (one + for each channel) from a four pin push/pull output configuration with said limitations. Sorry if I wasnt clear and thank you very much for chiming in.

Rob Withey · 02-17-2009, 04:03 AM

Yep, and you can do this with a ground loop isolator.
Connect your balanced lines into the inputs. Tie the grounds of the outputs together for your common ground. The two remaining outputs are your positive lines.

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