Dual input hum.

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#22
You said that you have followed grounding diagram... did you mean that picture in post #17?

I have one question about your input socket grounding scheme. Have you connect that like in picture above.... I mean that input socket frame is connected also to the amplifier and to the star point?
And output is connected also to amplifier and starpoint?


Second question. You have connect starpoint to chassis ground via 10uF / 10ohm so have you connect mains earth also to this chassis ground point? Or where you have connect that mains earth?
 
#23
Eccu said:
You said that you have followed grounding diagram... did you mean that picture in post #17?

I have one question about your input socket grounding scheme. Have you connect that like in picture above.... I mean that input socket frame is connected also to the amplifier and to the star point?
And output is connected also to amplifier and starpoint?


Second question. You have connect starpoint to chassis ground via 10uF / 10ohm so have you connect mains earth also to this chassis ground point? Or where you have connect that mains earth?
Click to expand...


Hi,

Yes post #17 is the diagram.

First of all, I rebuilt my monoblocks into one chassis. I Grounded my inputs seperately from the rca input ground each to the star ground only.

Each 1000uF cap grounded seperately to the star.

The bottom of my case in not metal (wood) and so the star ground is isolated.

My PSU is seperate and is grounded to the mains earth but is not (at this point) connected to amp ground. I know it SHOULD be and will more than likely try the method in the diagram. I will run an additional ground back from the star to the psu and connect to eart as in the diagram but cannot guarantee it will be hum free. The diagram shows the whole star residing in the PSU. Too many wires on the connector, for me anyway. This is where I deviated from Moamps suggestion although suggestions have worked well so far so I have no reason not to believe it will work.

I found this diagram on the passdiy.com. http://www.passdiy.com/pdf/zen-v5-hires.pdf. Check out page 7. Nelson Pass uses this scheme to connect to mains ground/earth.

Hope this helps
 
#27
Overlooked ground path?

My thought, for what it's worth.

I have been looking at the schematics posted above.

I think the ground wiring is still not shown completely - isn't there a connection between ground on the right-hand channel at the source (i.e. pre-amp) and the left-hand channel ground at the source (i.e. pre-amp).

This has the effect of making a long thin loop with the shields of the two signal leads as its perimeter

Perhaps you could try the effect of cutting one (only one!) of the shields at some convenient point? Or minor rewiring with that in mind?
 
#28
Re: Overlooked ground path?

PhilW said:

I think the ground wiring is still not shown completely - isn't there a connection between ground on the right-hand channel at the source (i.e. pre-amp) and the left-hand channel ground at the source (i.e. pre-amp).
This has the effect of making a long thin loop with the shields of the two signal leads as its perimeter
Perhaps you could try the effect of cutting one (only one!) of the shields at some convenient point? Or minor rewiring with that in mind?
Click to expand...

Hi,

Thru signal ground wires (from input RCA to star ground and back to the another RCA) "power" current don't flows. This is here important. Any interconnect with separate ground-shield makes some kind of "long thin loop". Anyway, this grounding scheme was built for two separate monobloks where cutting one shield can't help to solve humming problems. IMHO

Regards
 
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