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Old 14th January 2006, 06:34 PM   #1
akunec is offline akunec  
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Default XLR / Balanced cable chipamp

does anyone have a design to use a chipamp differentially with XLR cables... I have a DCX 2496 and would like to stay balanced to minimize noise.
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Old 14th January 2006, 07:03 PM   #2
XELB is offline XELB  
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Since you allready have a source with ballanced output, I think you can buy four LM3886 single ended boards and use two per channel.
Some members sell LM3886 boards
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Old 14th January 2006, 07:05 PM   #3
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Not sure about the pin layout.
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Old 14th January 2006, 07:20 PM   #4
paulb is offline paulb  
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http://www.diyaudio.com/forums/showt...901#post212901
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Old 14th January 2006, 07:22 PM   #5
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akunec is not asking for bridge, he is asking for a balanced design.
You don't need two chips, a single LM3886 chip converts balanced to unbalanced, like any op-amp does, and of course with the advantage of noise rejection.
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Old 14th January 2006, 07:32 PM   #6
XELB is offline XELB  
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Quote:
Originally posted by carlosfm
akunec is not asking for bridge, he is asking for a balanced design.
You don't need two chips, a single LM3886 chip converts balanced to unbalanced, like any op-amp does, and of course with the advantage of noise rejection.

He said that he would like to stay balanced.....

You are advising to convert the balanced input to a single ended output...
Or it's my confusion ?
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Old 14th January 2006, 07:39 PM   #7
joster is offline joster  
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I've been considering the same thing, also for use after a DCX. I don't beilieve it should be too complicated. I think it needs reduced gain due to the higher input voltage from a balanced source, and from what I've seen the input impedance is usually lower, perhaps to keep the resistance in the feedback loop close to the input impedance. I don't know much about this, but I think others might be interested considering the size of the DCX thread and the ease of implementation of chipamps.

You could also put a balanced input buffer in front of the chipamp, but i would try to do it without added components.

I have no pcb software design skills.

Perhaps one of the gc gurus would start us on the path?
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Old 14th January 2006, 07:42 PM   #8
poobah is offline poobah  
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akunec,

Post the schematic of your LM3886 circuit... We can show you how to make a differential (balanced) input amplifier.



EDIT:

Do you want to drive XLR cables with chip amp?

Or drive a chip amp with XLR cables?

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Old 14th January 2006, 07:42 PM   #9
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Quote:
Originally posted by XELB
He said that he would like to stay balanced.....
He didn't say he wanted balanced up to the speakers.

Quote:
Originally posted by XELB
You are advising to convert the balanced input to a single ended output...
Or it's my confusion ?
That's right, balanced input to the LM3886, which converts to unbalanced out to the speakers.
This way the (power) op-amp rejects any noise present in the signal, bridged does not.
That's what akunec means by 'would like to stay balanced to minimize noise'.
'Stay balanced' between the DCX 2496 and the amp, that's it.
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Old 14th January 2006, 07:48 PM   #10
XELB is offline XELB  
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But Carlos, you can also minimize noise and lower the distortion if the ouput is differential...

I think it's better that akunec explain the context.
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