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Old 5th December 2012, 06:24 PM   #51
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Quote:
Originally Posted by AudioSan View Post
this is NOT what i told you to do. this is the worst way to connect signal ground.
Why? Can you please elaborate? Thank you!
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Old 5th December 2012, 06:29 PM   #52
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it was not a answer to too it was for TS
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Old 5th December 2012, 06:30 PM   #53
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Quote:
Originally Posted by Tube_Dude View Post
Why? Can you please elaborate? Thank you!
TS has now created a common impedance with the red wire going to power grond. all voltage that drops over that wire is shared, and thus even to the input ground.

VERY BAD indeed.
at least try my previous scheme (re-attached), or this Alternative option for your PSU board, with star ground.

i've attached your original too.
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File Type: jpg f5hum73.jpg (68.9 KB, 97 views)
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Last edited by powerflux; 5th December 2012 at 06:45 PM.
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Old 5th December 2012, 06:49 PM   #54
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Originally Posted by AndrewT View Post
Take a wire or trace from the Zero Volts connection to a remotely located Main Audio Ground. this link can be long or short or very short.
You are wrong!!!! This link MUST be very short, because the currents from BOTH speakers will pass thought it and will develop a spurious voltage.

Is a common mistake to think about Ground like only the 0 Volts reference, actually the power supply capacitors are were the AC currents close. Ideally we must have a "short" for AC between Positive, Negative and Zero Volts Ground.

The place where this "short", for AC, take place is the main filter capacitor, so the link from the capacitors 0 volts to the 0 volts ground signal reference, will add to this AC impedance, and the link voltage drops will add to the power supply AC voltage. The input stage is very sensitive to this AC spurious voltage, because the "input" of the output MOSFETS are referenced to the positive and negative rail, in the configuration used (not the more usual follower configuration).

So, please keep the link the shorter as possible...
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Last edited by Tube_Dude; 5th December 2012 at 06:53 PM.
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Old 5th December 2012, 07:03 PM   #55
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Originally Posted by powerflux View Post

VERY BAD indeed.
at least try my previous scheme (re-attached), or this Alternative option for your PSU board, with star ground.

i've attached your original too.
Hi Powerflux

A AMP unhappily don't work without a source, so, think for a moment in your first option, the one you say is a better alternative. In the moment you connect a source, the commom ground of the source will shunt both RCAs grounds together, even worst, they do it remotely at the end of interconnect cables, and you end with a nice and BIG ground loop.

We must think in the concept of grounding, in real operation conditions...
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Old 5th December 2012, 07:08 PM   #56
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Originally Posted by Tube_Dude View Post
Hi Powerflux

A AMP unhappily don't work without a source, so, think for a moment in your first option, the one you say is a better alternative. In the moment you connect a source, the commom ground of the source will shunt both RCAs grounds together, even worst, they do it remotely at the end of interconnect cables, and you end with a nice and BIG ground loop.

We must think in the concept of grounding, in real operation conditions...
you are right
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Old 5th December 2012, 07:12 PM   #57
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Originally Posted by powerflux View Post
you are right
Cheers!
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Old 5th December 2012, 08:22 PM   #58
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Originally Posted by Tube_Dude View Post
Hi, Blink_PT

But you still have the hum? Even without interconnects, means, without nothing connected to the input RCAs?

I ask because i really don't understand it, from your last post.

Hello Jorge,

I already said above, I have no hum without interconnets.

Simply connect an IC that I hum in the opposite column, then call the two ICs and got such a hum in the two columns.

I've used all ICs I have, and they are many, shielded, unshielded, with only the side of the screen Amp, with only the screen side of the source. Everything, everything has been tried on ICs, since Arataca (space MIL 27500) to the most expensive.

The problem is that the F5, but where?
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Old 5th December 2012, 09:55 PM   #59
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Have you tried to lift the chassis ground? (CL60)
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Old 5th December 2012, 11:44 PM   #60
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Have you measured if CL60 is not burned? Try to short it for some tests ...
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