LM4780 Stereo Mode Grounding

daccordimark · 5th March 2010, 11:46 AM

Hi,
I am building one of the Audiosector LM4780 kits with each chip in stereo mode with one transformer and one rectifier board. Reading through all the posts I could find on grounding I am still confused as to how to do it with my configuration. Should I be using a version of this scheme?

http://www.diyaudio.com/forums/1518369-post77.html

I have isolated the chips from the heatsink as recommended but don't know where to go from here.

Any help gratefully received as I'm so close now to getting the amps working and can't wait to hear them,
Mark.

littlerick · 5th March 2010, 02:01 PM

I just grounded mains to chassis 1 each from chassis ground on boards and just grounded signal to the spots provided and not to chassis...

Gotta say the amp sounds awsome, I have both amps bridged though.

daccordimark · 5th March 2010, 02:28 PM

Thanks littlerick, I assume chassis ground is the pad marked chg on the underside of the boards. Am I right in thinking SG on the boards is the input ground from the RCAs and OG is the output ground to go to the speaker connections? I notice they are all connected together anyway when I test with a meter.
Mark.

littlerick · 5th March 2010, 03:00 PM

Yes that sounds about right. Make a lightbulb tester too... saves time n hassle.

5th March 2010, 11:46 AM	#1
daccordimark diyAudio Member Join Date: Dec 2008 Location: West Yorkshire, England	LM4780 Stereo Mode Grounding Hi, I am building one of the Audiosector LM4780 kits with each chip in stereo mode with one transformer and one rectifier board. Reading through all the posts I could find on grounding I am still confused as to how to do it with my configuration. Should I be using a version of this scheme? http://www.diyaudio.com/forums/1518369-post77.html I have isolated the chips from the heatsink as recommended but don't know where to go from here. Any help gratefully received as I'm so close now to getting the amps working and can't wait to hear them, Mark.

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5th March 2010, 02:01 PM	#2
littlerick diyAudio Member Join Date: Nov 2009 Location: Lincolnshire UK	I just grounded mains to chassis 1 each from chassis ground on boards and just grounded signal to the spots provided and not to chassis... Gotta say the amp sounds awsome, I have both amps bridged though.

5th March 2010, 02:28 PM	#3
daccordimark diyAudio Member Join Date: Dec 2008 Location: West Yorkshire, England	Thanks littlerick, I assume chassis ground is the pad marked chg on the underside of the boards. Am I right in thinking SG on the boards is the input ground from the RCAs and OG is the output ground to go to the speaker connections? I notice they are all connected together anyway when I test with a meter. Mark.

5th March 2010, 03:00 PM	#4
littlerick diyAudio Member Join Date: Nov 2009 Location: Lincolnshire UK	Yes that sounds about right. Make a lightbulb tester too... saves time n hassle.

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