Grounding problem question?

excetara2 · 19th August 2006, 05:46 AM

One of the grounds on my pre-amp for the output of the front speakers is messed up. It connects to the ground on the outside of the RCA's but not to the ground for the rest of the pre-amp. I was wondering the best way to fix this. I was just going to connect the pin to the ground of the other channels to get a common ground. This should work right. I was wondering if it would be better to just move the terminal to a spot I'm not using and replace it. The whole row of inputs uses the same terminals. Thanks.

AndrewT · 19th August 2006, 09:09 AM

Hi,
being from the other side, I'm having trouble following this.
Are the RCAs insulated from the chassis?
Do the other RCA grounds go to audio ground?

CarlosT · 10th November 2006, 01:48 PM

It's very tempting to let the RCA inputs ground to the chassis as they're bolted in instead of isolating these and going right to the "star ground" point via separate cables.

suspencefull · 10th November 2006, 01:50 PM

You recommend I open it up and ground to the star ground point on the board.

CarlosT · 10th November 2006, 01:50 PM

On a related question though...would it be OK to allow both grounds? In other words...don't sweat it with isolating the RCA input jack ground from the chassis but make sure to have a wire go to the "star grounding" point...kinda like parallel grounds?

AndrewT · 10th November 2006, 04:39 PM

Hi,
keeping the RCA ground mounted on the chassis is likely to be the worst mistake one can make.

The input is a voltage signal between line in and RCA ground. The amplifier tries to send an amplified version of this to the speaker.

If the RCA ground goes via the chassis to safety earth and then to audio ground and finally to signal ground on the PCB, it is following the worst route for picking up all forms of voltage and modulation interference on the input signal.

19th August 2006, 05:46 AM	#1
excetara2 diyAudio Member Join Date: Jun 2006	Grounding problem question? One of the grounds on my pre-amp for the output of the front speakers is messed up. It connects to the ground on the outside of the RCA's but not to the ground for the rest of the pre-amp. I was wondering the best way to fix this. I was just going to connect the pin to the ground of the other channels to get a common ground. This should work right. I was wondering if it would be better to just move the terminal to a spot I'm not using and replace it. The whole row of inputs uses the same terminals. Thanks.

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19th August 2006, 09:09 AM	#2
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	Hi, being from the other side, I'm having trouble following this. Are the RCAs insulated from the chassis? Do the other RCA grounds go to audio ground?

10th November 2006, 01:48 PM	#3
CarlosT diyAudio Member Join Date: Oct 2006	It's very tempting to let the RCA inputs ground to the chassis as they're bolted in instead of isolating these and going right to the "star ground" point via separate cables.

10th November 2006, 01:50 PM	#4
suspencefull diyAudio Member Join Date: Aug 2006	You recommend I open it up and ground to the star ground point on the board.

10th November 2006, 04:39 PM	#6
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	Hi, keeping the RCA ground mounted on the chassis is likely to be the worst mistake one can make. The input is a voltage signal between line in and RCA ground. The amplifier tries to send an amplified version of this to the speaker. If the RCA ground goes via the chassis to safety earth and then to audio ground and finally to signal ground on the PCB, it is following the worst route for picking up all forms of voltage and modulation interference on the input signal.