Several psu ground question.

KaffiMann · 11th April 2010, 09:11 AM

I am building an integrated amplifier, which needs several different psu's to work. And there will be two 48v battery banks in there as well. Will there be any problem connecting the center of two 48V banks, the - of several other dc supplies, and the mains ground together?

I guess this is what it's like when you have several different components in a sound system, so it is probably going to work fine, but i am building one separate box for all the psu's, and if there are any smart approaches to the issue, i hope someone has done the dirty work before.

Gordy · 12th April 2010, 03:05 PM

Hi,

Ground is a reference, so if they all need the same reference point then it should be fine.

When using a separate PSU box you could do this...
1. Connect mains ground directly to the PSU case, for safety.
2. Run a wire from there to the case of the Amp, again for safety.
3. Connect the PSU case safety ground point to the centre (reference point) of the PSUs in the PSU box. This becomes the 'star point'. Many people make this connection via a small resistor, about 10R 1W.
4. Run a wire from that star point to the Amp box. In the Amp box use this for all of your audio signal grounds. Do not connect it to the Amp case safety ground.

You now have...
PSU safety grounded
Amp safety grounded
PSU ground reference point
Ground return from Amp to PSU

Should work well.

11th April 2010, 09:11 AM	#1
KaffiMann diyAudio Member Join Date: Sep 2009	Several psu ground question. I am building an integrated amplifier, which needs several different psu's to work. And there will be two 48v battery banks in there as well. Will there be any problem connecting the center of two 48V banks, the - of several other dc supplies, and the mains ground together? I guess this is what it's like when you have several different components in a sound system, so it is probably going to work fine, but i am building one separate box for all the psu's, and if there are any smart approaches to the issue, i hope someone has done the dirty work before. __________________ Theory and practice are not the best of friends in real life. Theory suggest they should be, but practice shows they don't always combine that well.

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12th April 2010, 03:05 PM	#2
Gordy diyAudio Member Join Date: Nov 2006	Hi, Ground is a reference, so if they all need the same reference point then it should be fine. When using a separate PSU box you could do this... 1. Connect mains ground directly to the PSU case, for safety. 2. Run a wire from there to the case of the Amp, again for safety. 3. Connect the PSU case safety ground point to the centre (reference point) of the PSUs in the PSU box. This becomes the 'star point'. Many people make this connection via a small resistor, about 10R 1W. 4. Run a wire from that star point to the Amp box. In the Amp box use this for all of your audio signal grounds. Do not connect it to the Amp case safety ground. You now have... PSU safety grounded Amp safety grounded PSU ground reference point Ground return from Amp to PSU Should work well.

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