Well, I don't see any tendency of oscillation. When you have to decouple 1MHz to 1GHz from the power line...
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Nothing against whatever part you have available to try but the two parts you're going to compare should be same make/model to have a fair comparison.
Every make/model has a distinct sound signature, if you compare parts which are different both in value/rating and make/model you simply can't say what is making the difference... at least IMHO.
When I'll try the rail to rail decoupling with Elna RJHs we'll discover it 😉
I'm not sure that I've understood...
You have a problem with protection kicking-in?
Interesting, can you post something more elaborate on the FE thread?
While it's the grounding scheme I'm actually using without problems, connecting PGND to safety ground it's not the best scheme.
You should try to connect PGND to safety ground via a thermistor or a power resistor (1-10 Ohm 3-5W)
this information starts off misleading and becomes wrong as I read through ending up with a build that is DANGEROUS.
If you don't know how and why the Protective Earth (PE) works to prevent users being killed, then don't comment nor advise. Ask for information instead.
Maybe I've misunderstood...OK, I ask for information then...
What exactly is wrong in my post and what is the right way to ground?
Thanks in advance
The PE is there to conduct Mains Fault Current back to Earth. This is to prevent a piece of faulty equipment killing the user. There is no choice here, using the PE is compulsory. I cannot understand countries that allow mains electricity to be used without PE.
The PE works by taking any Mains current from the chassis to Earth. That requires the chassis to be connected directly to PE. Nothing in between.
But there is a secondary rule, of almost equal importance.
All exposed conductive parts must be connected to Safety Earth.
This means metal coated knobs, RCA terminals, Speaker terminals, etc. must be connected to the Main Audio Ground and that Audio Ground must be able to pass Fault Current to the PE.
That Fault Current can be thousands of amperes.
Have you tried passing Fault Current through a Power Thermistor?
Which blows first? The mains fuse or the Power Thermistor? The route for Fault Current must survive longer than it takes for the fuse to rupture and the arc to extinguish.
I have reported a direct on line test of Fault Current to PE. I used a 10r 600mW resistor. It survived undamaged.
I used a ~100nF 63V plastic film capacitor. It survived undamaged.
Neither of these components passed Fault Current to PE.
What really matters is the 25A or 35A bridge rectifier wired as paralleled diodes. This is what passes the Fault Current to PE. the 25A bridge survived undamaged.
The wires to connect the mains input to the chassis survived undamaged.
The fuse holder blow off it's little flip over cover. One fuse and it's end caps was never found. The other fuse left two badly damaged (partially melted) end caps and virtually no glass.
The inside of the fuseholder (integrated into an IEC socket) was covered in a black dust.
I cleaned out the fuseholder and after checking put it back to "normal" use.
The important part was that, what I was recommending had been tested and proved to work as intended.
If you use a Resistor alone, are you prepared to test it in the Fault Current situation?
I can confirm it makes an almighty "BANG" and sends particles all around the room. Protect your self.
Linked with this is why I always recommend close rated fusing. A close rated fuse will rupture in anywhere from 50% to 0.1% of the time that the "bigger" fuse will take to rupture.
All of this has been posted by many Members on this Forum.
If you want to work with Mains electricity, you must be prepared to do the research to protect yourself and your loved ones.
It is completely irresponsible to give dangerous advice simply because you have not informed yourself.
The PE works by taking any Mains current from the chassis to Earth. That requires the chassis to be connected directly to PE. Nothing in between.
But there is a secondary rule, of almost equal importance.
All exposed conductive parts must be connected to Safety Earth.
This means metal coated knobs, RCA terminals, Speaker terminals, etc. must be connected to the Main Audio Ground and that Audio Ground must be able to pass Fault Current to the PE.
That Fault Current can be thousands of amperes.
Have you tried passing Fault Current through a Power Thermistor?
Which blows first? The mains fuse or the Power Thermistor? The route for Fault Current must survive longer than it takes for the fuse to rupture and the arc to extinguish.
I have reported a direct on line test of Fault Current to PE. I used a 10r 600mW resistor. It survived undamaged.
I used a ~100nF 63V plastic film capacitor. It survived undamaged.
Neither of these components passed Fault Current to PE.
What really matters is the 25A or 35A bridge rectifier wired as paralleled diodes. This is what passes the Fault Current to PE. the 25A bridge survived undamaged.
The wires to connect the mains input to the chassis survived undamaged.
The fuse holder blow off it's little flip over cover. One fuse and it's end caps was never found. The other fuse left two badly damaged (partially melted) end caps and virtually no glass.
The inside of the fuseholder (integrated into an IEC socket) was covered in a black dust.
I cleaned out the fuseholder and after checking put it back to "normal" use.
The important part was that, what I was recommending had been tested and proved to work as intended.
If you use a Resistor alone, are you prepared to test it in the Fault Current situation?
I can confirm it makes an almighty "BANG" and sends particles all around the room. Protect your self.
Linked with this is why I always recommend close rated fusing. A close rated fuse will rupture in anywhere from 50% to 0.1% of the time that the "bigger" fuse will take to rupture.
All of this has been posted by many Members on this Forum.
If you want to work with Mains electricity, you must be prepared to do the research to protect yourself and your loved ones.
It is completely irresponsible to give dangerous advice simply because you have not informed yourself.
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Semi-related, I have had many shocks from our 120VAC here in the States. It wasn't bad because I wasn't grounded. The single 220 shock I experienced threw me six feet across the room. I often wonder about the increased hazard of the higher power in other countries. It can happen so fast.
"All exposed conductive parts must be permanently (and directly!) connected to PE" seems a good thumb rule approach.
If a conductive part cannot be tied to PE (like speaker output binding post), then you have to avoid having it exposed in order to match the thumb rule.
If a conductive part cannot be tied to PE (like speaker output binding post), then you have to avoid having it exposed in order to match the thumb rule.
the safety scheme works by triggering the differential breaker (AKA Residual-current device): any unbalance current (that is any current not flowing back through neutral but flows through earth instead) above the safety device set point (max 30mA here in Italy) will trigger the breaker and cut the mains. Hopefully BEFORE anyone will come in contact with the failing appliance.
Although from a normative point of view things may be different, from a technical (and safety) point of view there are no problem whatsoever as far as you don't break (or substantially limit) the AC&DC conduction from circuit ground to PE in presence of dangerous voltages between the two.
Thus from a technical (and safety) point of view there are absolutely no problem if you insert a small valued resistor/thermistor, anti-series zener diodes, inductor, etc between signal ground and PE to open ground loops or limit their nasty effects.
Perhaps you may not get CE certification that way, but that's another story. 😉
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We in the UK generaly survive because our regulations are very much "belt and braces" in their approach.
One fault should never kill anybody.
It usually takes at least two Faults to make our electrical equipment deadly.
The statistical chances of those two faults occurring and remaining so, while someone touches/adjusts/leans against, the double faulted equipment are relatively small.
Like fuse at distribution board and fuse at plug top.
Like earthed chassis and fuse on Live (Hot).
Like earth bonded metal work around the house and continuous non jointed bonding wire all the way back to the distribution board.
Polarised socket outlets and fused Live.
The list is not quite endless, but it (belt & braces) results in few accidental deaths and attracts criticisms from other Nations whose regulations are much more lax.
One fault should never kill anybody.
It usually takes at least two Faults to make our electrical equipment deadly.
The statistical chances of those two faults occurring and remaining so, while someone touches/adjusts/leans against, the double faulted equipment are relatively small.
Like fuse at distribution board and fuse at plug top.
Like earthed chassis and fuse on Live (Hot).
Like earth bonded metal work around the house and continuous non jointed bonding wire all the way back to the distribution board.
Polarised socket outlets and fused Live.
The list is not quite endless, but it (belt & braces) results in few accidental deaths and attracts criticisms from other Nations whose regulations are much more lax.
I wish I had access to the regulation/s that govern this situation. My approach is very much based on anecdotal quotes from others who I have presumed are well versed in that subject.
I had a short discussion with a Member last week about an apparent difference in interpretation between the UK and his Germany. I don't know if there was a difference in the regulation or that we amateurs (me included) were simply reading it differently.
First of all thanks for the interesting post 🙂
So, If I understand correctly, the only method you consider safe is connecting PNGD to safety ground via ESP ground breaker or at least a diode bridge (as parallel diodes).
I suppose that also PGND to safety ground is safe but not advisable for ground loops and/or noise injection problems, right?
Probably I've missed it, BTW most of Nelson Pass' PS uses thermistors as the only path for fault current.
I've read somewhere also about the single power resistor as an effective method.
Maybe my informations are not complete or right and I appreciate your suggestions.
I appreciate less this sentence...
I've simply trusted mr. Pass:
The power supplies of each channel are isolated from each other
electrically, except for a thermistor on each which connects the circuit
ground to the chassis and earth ground. In this way ground loops are
prevented, as the channels will typically share ground only at the source,
but the thermistors stand by to conduct AC line voltage to ground until the
fuse blows, in case of transformer or other such failure.
(from F1 service manual)
And many others, BTW. 😉
So, If I understand correctly, the only method you consider safe is connecting PNGD to safety ground via ESP ground breaker or at least a diode bridge (as parallel diodes).
I suppose that also PGND to safety ground is safe but not advisable for ground loops and/or noise injection problems, right?
Probably I've missed it, BTW most of Nelson Pass' PS uses thermistors as the only path for fault current.
I've read somewhere also about the single power resistor as an effective method.
Maybe my informations are not complete or right and I appreciate your suggestions.
I appreciate less this sentence...
I've simply trusted mr. Pass:
The power supplies of each channel are isolated from each other
electrically, except for a thermistor on each which connects the circuit
ground to the chassis and earth ground. In this way ground loops are
prevented, as the channels will typically share ground only at the source,
but the thermistors stand by to conduct AC line voltage to ground until the
fuse blows, in case of transformer or other such failure.
(from F1 service manual)
And many others, BTW. 😉
just make sure that whatever you put between the signal ground and PE can safely withstand at least more current than the local fuse(s) will allow. 😉
Of course the case and PT (core and screen if present) must be always directly connected to PE. As should be any other metal part which can be earthed without problems.
To avoid ground loops, signal input/output connectors must be kept isolated from the case.
Based on my experience, when too large capacitance is used where Y caps should be used, the leakage current will create small shock. This tells me that protective grounding does not work as expected. This had been verified in a qualified lab with earth ground according to requirements. However, since the regulation requires it, a commercial product should adhere to it. Class II appliances do not have connection to earth ground, thus have a different set of insulation requirements.
Dario, in my switching power, loading it with too much capacitance will trigger the protective circuit.
Dario, in my switching power, loading it with too much capacitance will trigger the protective circuit.
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If your referring to what most would call a "GFCI", they are for "extra" protection in certain situations, I would certainly not rely on them, simply because they are not reliable.
Add to this a GFCI won't protect you from stored voltage in your device amplifier should it have such a fault.
I had used a low value resistor between Signal Return and Main Audio Ground.
That is until a Member posted a schematic in which I noticed he had a diode across that resistor.
That got me thinking about the exposed RCA barrel at the other end of an interconnect.
I now use inverse parallel diodes (1n400x) across all my low value resistors that may have to pass some fault current, irrespective of which end of the interconnect cable has the fault.
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I don't understand... what are you referring to?
In the My_Ref there's no single place where a Y cap should be used apart the connection between IEC/fuse/transformer primaries...
Ok, so you were referring to the switching PS protection... now it's clear, thanks 🙂
We ran through some speakers and amps in listening tests. Very interestingly, the little modded amp presented more detail than another class A amp. Sound stage was pretty much the same, low frequency seemed more correctly damped to me while some preferred a looser beefier low end with small speakers. Sorry for not revealing the exact models because I did not really take care to note what they were. I am happy, but also see some more room for improvement.
I am talking about power ground protection in general. X and Y caps have very specific requirements when used for mains power filtering. What I am saying is that it's been confirmed you will have a shock when large currents pass through the ground line of the mains regardless whether you meet the requirements or not.
I too would not appreciate that being said to me. But, if I was that irresponsible, then maybe that type of message is what I would need to wake me up.
I stand by what I said. Looks like you have been wakened up.
