Please read this article , I will post the schematic in the next post :
Ground Loops and Proper Grounding by FM Acoustics
- Thread starter Amir
- Start date
Ground Loop is not good for perfect sound reproduction so FM Acoustics recommends just only one path to ground is allowed in circuit design and if you look at the picture there is no ground loop even in chassis ground schematic and the chassis ground connected to earth wire just at pre amplifier .
Chassis ground is not connected to signal ground , every component has his own internal signal ground isolated from chassis ground.
chassis ground acts like faraday cage to prevent circuits from emi/rfi or any other interference
chassis ground acts like faraday cage to prevent circuits from emi/rfi or any other interference
Rule one: no ground loop
Rule two: perfect shield
Rule three: perfect low impedance building earth
Rule four: take away cables from each other
Rule two: perfect shield
Rule three: perfect low impedance building earth
Rule four: take away cables from each other
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XLR Balance Cable has 4 connection not 3 connection.
The cd player chassis ground connects to female XLR connector and female XLR connector connects to cable shield and at the end the cable shield connects to male xlr connector and xlr connector connects to pre-amplifier chassis ground .
It means the cable shield connects two chassis together.
There is three cable inside of XLR cable :
Pin 1 : wire number 1 transfer signal ground between two components
Pin 2 : wire number 2 transfer non-invert signal between two components (EU standard)
Pin 3 : wire number 3 transfer invert signal between two components
The cd player chassis ground connects to female XLR connector and female XLR connector connects to cable shield and at the end the cable shield connects to male xlr connector and xlr connector connects to pre-amplifier chassis ground .
It means the cable shield connects two chassis together.
There is three cable inside of XLR cable :
Pin 1 : wire number 1 transfer signal ground between two components
Pin 2 : wire number 2 transfer non-invert signal between two components (EU standard)
Pin 3 : wire number 3 transfer invert signal between two components
The most important point in order to avoid ground loops is that signal ground and chassis ground are connected at only one point of the set-up.
In my set-up this point is inside the power amp. I have no hum, not even at full volume with 99dB sensitivity speakers.
Matt
In my set-up this point is inside the power amp. I have no hum, not even at full volume with 99dB sensitivity speakers.
Matt
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This is incorrect information.
There's 3 connections on an XLR. Some cable ends connect the shield to the body. But there is not 4 connections unless it's a different type of cable than used in audio playback/interconnect. In fact the most standardized point made in all engineering for balanced cables is the Pin 1 issue. Pin 1 is always connected to chassis with the shortest possible distance, because it keeps the shield in tact as best as possible. This keeps the whole signal in an envelope of shield -including in the appliance.
Also you don't need a ground for signal because it's balanced. The "return" is the opposite phase wire.
There's no debate here. These are facts.
As far as ground loops, XLR doesn't carry a ground to circuit, and the type of circuit cancels common mode noise. There shouldn't be any loop that is perceivable. You have double the parts, but that issue is gone. However not all manufacturers make balanced gear so it's not always true that you're getting any benefits.
Your drawing is incorrect as well. The CD player if it's class 2 doesn't have an earth ground in it. The chassis could be connected via pin1, but that would be fairly unusual and maybe not code. The drawing doesn't make that much sense given that it has an extra connection. There is no purpose to the earth connection inside a power amp either as it doesn't do signal and won't do shielding if it isn't connected to chassis. At best it shields up until termination at the circuit - which doesn't seem to be what you're indicating because you'd be making loop with it were it connected.
Again there isn't 4 connections in any standard XLR cable... And you would never connect chassis via a link that wasn't earth grounded because otherwise it would simply do nothing at all (also making the shield on the cable ineffective). Your principle of perfect shielding doesn't exist as you explain it.
I'm not sure how you got anything you did from the PDF except that some FM gear is class 2 so it can't participate in the grounding issue in the same way. Feel free to ask questions.
There's 3 connections on an XLR. Some cable ends connect the shield to the body. But there is not 4 connections unless it's a different type of cable than used in audio playback/interconnect. In fact the most standardized point made in all engineering for balanced cables is the Pin 1 issue. Pin 1 is always connected to chassis with the shortest possible distance, because it keeps the shield in tact as best as possible. This keeps the whole signal in an envelope of shield -including in the appliance.
Also you don't need a ground for signal because it's balanced. The "return" is the opposite phase wire.
There's no debate here. These are facts.
As far as ground loops, XLR doesn't carry a ground to circuit, and the type of circuit cancels common mode noise. There shouldn't be any loop that is perceivable. You have double the parts, but that issue is gone. However not all manufacturers make balanced gear so it's not always true that you're getting any benefits.
Your drawing is incorrect as well. The CD player if it's class 2 doesn't have an earth ground in it. The chassis could be connected via pin1, but that would be fairly unusual and maybe not code. The drawing doesn't make that much sense given that it has an extra connection. There is no purpose to the earth connection inside a power amp either as it doesn't do signal and won't do shielding if it isn't connected to chassis. At best it shields up until termination at the circuit - which doesn't seem to be what you're indicating because you'd be making loop with it were it connected.
Again there isn't 4 connections in any standard XLR cable... And you would never connect chassis via a link that wasn't earth grounded because otherwise it would simply do nothing at all (also making the shield on the cable ineffective). Your principle of perfect shielding doesn't exist as you explain it.
I'm not sure how you got anything you did from the PDF except that some FM gear is class 2 so it can't participate in the grounding issue in the same way. Feel free to ask questions.
I solved all of this by implementing a Shunyata Altaira. Made a significant decrease in noise.
This is probably an old document, previous to modern electrical regulations that make a connection between earth and metal chassis mandatory in EC for all equipment - although I do not know about Switzerland codes, I can't imagine they are less stringent than EC. If the direct connection between chassis is broken we risk safety problems. The equipment as shown could not not be exported to EC countries.
Earth isn't required to be connected in all appliances. The code for CE and UL, and manufacturing standards is based on how and what type of insulating factors are between specific voltages and outer casement enclosures. There's lots of two prong things out there.
There's a host of points but "double insulated" is typical, however "reinforced insulation" is also a deployed way of doing it. The process also involves drop tests and such, as there are certain requirements for how wires are terminated between parts and how secure they are. I'm not going to bore everyone with PDF's in multiple languages etc... but anyways. Unless Swiss ignore CE now, you're incorrect.
No way I was addressing "all equipment". I was focusing on power amplifiers such as the high power FM Acoustics power amplifiers that must be grounded. This was my only message, I was not addressing some CD players, hair driers or vacuum cleaners. CE regulations even obliged manufacturers to use insulated speaker terminals and banished the 4mm in speaker cables, as they can be inserted in our power plugs.
No need to re-post data on CE or UL certification - we had threads on the subject before in WBF, including post of known manufacturers and experts.
Yes but the power amplifiers can be Class II. It often requires custom transformers but they can be.
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