Ground Loop problem - Page 2

jleaman · 28th April 2006, 03:26 PM

Quote:

Originally posted by Mad_K
Are you using R0? What value?

R0? huh

khaho · 28th April 2006, 04:30 PM

Quote:

Originally posted by jleaman
And here is a link to my crappy drawing to how it is all connected.

http://jleaman.ath.cx/aleph/testing-psusm.jpg

Is -IN really not connected at all ? It should be connected in SE too.

Mad_K · 28th April 2006, 07:50 PM

Quote:

Originally posted by jleaman

R0? huh

-IN should be connected to SG, but that's not creating a ground loop.
R0 should be 3R3@3W (according to A30 sch) or jumpered.

jleaman · 28th April 2006, 08:28 PM

Quote:

Originally posted by Mad_K

-IN should be connected to SG, but that's not creating a ground loop.
R0 should be 3R3@3W (according to A30 sch) or jumpered.

I don't understand. and my other mini a's not in this chassi work 100% with out any hum only this one in a chassis.

jleaman · 29th April 2006, 06:18 AM

Ok i did what you suggested MAD_K but there is still hum. It sounds like it is more lighter but less deeper now. Now to test and see if i should be shielding the interconnect cable now from the pcb to the rca jack..

Mad_K · 29th April 2006, 10:00 AM

So what value did you use for R0?. Also, do you use a 10R/5A thermistor from GND (on psu board) to the chassis/Protective Earth? Both of these components are used to supress ground loops.

jleaman · 29th April 2006, 05:15 PM

Quote:

Originally posted by Mad_K
So what value did you use for R0?. Also, do you use a 10R/5A thermistor from GND (on psu board) to the chassis/Protective Earth? Both of these components are used to supress ground loops.

R0 is = 3.0Ohm @ 3 watt

and i have a thermister on the ac side of the ac plug but not on the gnd i could try one there but i doubt it will do any thing. I have tried removing the ac gnd from the circuit and it does nothing.

mpmarino · 29th April 2006, 11:11 PM

What if you tried a 'series' ground. Take your ground from the psu to one amp board, and just ground the other amp board at the first amp board...see below. It worked for me on my mini a. Actually, it's the only thing that worked for me.

jleaman · 30th April 2006, 12:22 AM

Quote:

Originally posted by mpmarino
What if you tried a 'series' ground. Take your ground from the psu to one amp board, and just ground the other amp board at the first amp board...see below. It worked for me on my mini a. Actually, it's the only thing that worked for me.

Where do you want the speakers Ground connected to ?

Mad_K · 30th April 2006, 01:25 AM

I would have tried to connect SG (RCA GND) to the other side of R0 (near Z4).

29th April 2006, 10:00 AM	#16
Mad_K diyAudio Member Join Date: Sep 2002 Location: Norway	So what value did you use for R0?. Also, do you use a 10R/5A thermistor from GND (on psu board) to the chassis/Protective Earth? Both of these components are used to supress ground loops. __________________ Mads K

30th April 2006, 01:25 AM	#20
Mad_K diyAudio Member Join Date: Sep 2002 Location: Norway	I would have tried to connect SG (RCA GND) to the other side of R0 (near Z4). __________________ Mads K

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29th April 2006, 06:18 AM	#15
jleaman Banned Join Date: Apr 2002	Ok i did what you suggested MAD_K but there is still hum. It sounds like it is more lighter but less deeper now. Now to test and see if i should be shielding the interconnect cable now from the pcb to the rca jack..