LM1875 hum - Page 3

xecluded · 5th February 2010, 03:00 PM

Quote:

Originally Posted by gootee

In your picture in post 13, it shows three power inputs, for AC18V/Gnd/AC18V. Those are probably for yellow, black, yellow from your transformer. Those terminals are not shorted together. So they will not short the transformer.

You need both yellow wires, connected as described, in order to have the on-board AC-to-DC power supply develop both positive and negative DC voltages. Without that happening, the circuit will not work correctly.

I will wire all three yellow/black/yellow and keep you update next week. Thanks.

xecluded · 18th February 2010, 10:51 PM

That did it - the hum went away after I hookup all 3 yellow/black/yellow wires. Thanks all for your help.

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18th February 2010, 10:51 PM	#22
xecluded diyAudio Member Join Date: Jul 2008 Location: 10,000 lakes	That did it - the hum went away after I hookup all 3 yellow/black/yellow wires. Thanks all for your help.