dedicated mains earth

[manisandher]

Hey Joachim, from the link:

Whilst a definite safety feature when used as designed, like all things electrical PME presents some risk potential for those tempted to idly bung in a 'hifi' earth. If the house supply is PME then idly adding a local earth spike in addition to the bonded neutral has the effect that your house could end up as the safety earth route for 10-100 houses in the area. For example in the case of a broken neutral elsewhere in area supplied by the same substation transformer the multiple bonding, and all the leakage currents from your neighbourhood's hundreds of bits of inlet-filtered equipment /SMPS now sees your hifi's earth. Do you still want to rely on your earth spike ?

The Right Way

There is nothing wrong with connecting a local earth providing that it and the earth cable connected to it through your house can carry such a fault current. If you choose to add an earth spike it can be done on a PME system but only in this way: it must be bonded to the (PME) earth bonding point at the consumer unit only, using a conductor of at least 16mm2

Quite frankly, I think it's clear that adding just an earth spike is pretty useless...

BUT...

This is not the case in my setup. I am using an isolation transformer and have my earth spike (actually a 3m long copper cylinder with electrolytes to ensure constant low impedance to earth) bonded to the Neutral output of the transformer. My earth acts as a true safety earth for only the dedicated line and not the rest of the house or neighbourhood. This is a totally different setup to the one described in the document.

I think the real conclusion is just leave the safety earth alone. (Edit: Unless you want to go through the hassle of installing an isolation transformer. But I wouldn't recommend it - see next post.)

Mani.

[manisandher]

Following on from the above post...

When I first installed my dedicated low-impedance AC mains line, 15KVA isolation transformer and dedicated earth (bonded to Neutral output of isolation transformer), I was disappointed with the sound. I had such high expectations, and they were totally dashed. On the one hand, the sound was 'cleaner' in the sense that there was less hash, but on the other the dynamics were compressed. I spent a fortune installing all this and was determined to find a solution.

My feeling was that the isolation transformer was increasing the impedance of the AC mains line, sort of 'slowing' everything down. The system simply couldn't keep up with the transients in the music. This increased impedance was perhaps creating a modulation effect between the amps and the NOS1a. So the solution was to have some device sitting immediately after the isolation transformer to decrease the impedance. It would have to have some sort of store of charge in order to do this. I went for a PurePower P2000 battery regenerator, with a large SMPS and class-D output.

The PP2000 definitely improved the dynamics. I was right! But... it also added a tremendous amount of noise to the system. And you can't do this with 118dB sensitive horns. So I switched back to just powering everything off the house mains, and really the sound was pretty much the same. All this expense for absolutely nothing.

But then I had the idea that a good AC regenerator with linear power supply and class-AB output. The obvious contender was one of the PS Audio units. Because the objective was to reduce AC impedance as much as possible, I went for their large P10 unit.

And the sound has been transformed. Exactly how I expected it to be when I set off on the dedicated AC mains journey.

Was it all worth it? Up until a couple of months ago, I would have said no. I think sticking to good old house mains is OK. This is how Paul (Scroobius) is currently powering his system, and it sounds bloody good.

But with the introduction of the Intona, I now feel having a dedicated AC mains line for the NOS1a and amps starts to make a lot more sense. If you want to isolate the dedicated AC line as much as possible, then you'll need an isolation transformer and impedance lowering device. And now things start to get very expensive, and perhaps not worth it.

Just my thoughts...

Mani.

[acg]

...and even if the monitor is one one ring and the AudioPC on another they are still electrically connected by the cable between them, so the noise has a direct path."

Anthony

Hi Anthony,

Thank you for sharing your experience.

For clarification, how do you see the monitor and PC electrically connected if we use an optical HDMI or DVI connector?

Especially if they are on a separate earth, and possible even on a different phase (I have 3 phases in triangle at my house).

Thanks,
Diede

Might not be a direct electrical connection, but it is still there.  I remember the Adnaco optical usb solution that promised so much but delivered so little...the theory as to why that did not work is that it is the conversion from optical to electrical that creates the noise.  I personally would not bother with it for a monitor...the RDC solution that Peter has worked into XXHE is the optimum arrangement.

Think about it this way...at the moment I am using a cpu without an inbuilt gpu...and I am not using a graphics card either (it's just not in the case) so my AudioPC has zero ability to output a graphics to a monitor...and it is the best sound I have ever had.


EDIT:  I have two XXHE computers here that are identical apart from the cpu:  my Xeon and the other i7-3790K (I think).  On the face of things and without putting too much effort into finding a reason why, I noticed that my Xeon cpu sounds better than the i7 and I think that may possibly be because the Xeon does not have inbuilt graphics whereas the i7 does.  I really do need to listen further to this and make a definitive judgement, but those are my preliminary observations.  Maybe I should do that this coming week.

[PeterSt]

Hi Anthony,

It is the 3690K in there and it has no built in graphics.
But mind the difference in clock speed of the CPU's in both cases. Maybe there's a difference there.

Regards,
Peter

[acg]

Hi Anthony,

It is the 3690K in there and it has no built in graphics.
But mind the difference in clock speed of the CPU's in both cases. Maybe there's a difference there.

Regards,
Peter

Oh well, next theory then.  Will do some better comparisons next week.

[toddn]

So I had a thought/question.

Here in the US, we have two 120v hot lines and a neutral. So generally we have all our consumer electronics run off 120v and the feed is inherently unbalanced. In my current situation, there is really no reason why I couldn't run everything at 240v(either selectable input voltage on the equipment primaries or easily modifiable solutions). I would then have 2 hot lines and the ground tied to the neutral, so a balanced circuit.

Wouldn't this be a preferable configuration?

[DickieCornell]

Hi i am new here and also looking to install a system.
Can you please tell me about your Siemens system, what are its specifications?
Also what are the specifications for your DAC?
What is the need of the fuses for the tuning, please clear me this concept?

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