Stop feedback from capacitors into power...

Destroyer OS

Member
2005-11-14 11:09 pm
PNW
First I have poor wiring in my apartment...

I have a problem with AC filter capacitors feeding back into my system, or the other power around.

I had to get rid of the neutral to ground filter all together because the ground was so poor that it would feed back into the neutral and give extensive noise in all of the system. It sucked. I think it was a case of looking for least resistance or something because in the past it has been the best digital filtering I have achieved.

The mains however... anything not on the AC filter (ever seen a Audience Adept, that is essentially what I made without teflon capacitors) gets noise... way too much.

I am starting to wonder if there is a way to flatten what is filtered out. Know what I mean? I am thinking of the attenuated signal by the capacitors being turned into DC, bled off through a resistor/light-bulb, something... hell I even thought about wiring a battery in that provided the current but one I am unsure how long it would last. (mains positive and battery positive connected with large resistor, and negative of battery connected to negative of capacitors, with positive of capacitor connected to mains positive) Sounds plausable huh? Two however is that I have never seen 115v batteries.

Unfortunately I am not coming up with any decent solutions, so I was thinking maybe someone on here would have an idea. Basically it does not matter how the frequency of voltage changes in the attenuated range so long as it is not re-entering the house circuit. If I solve this I can get the better digital filtering with the neutral to earth ground.
 

multisync

Member
2008-01-31 10:34 pm
Carp
If your apartment building is very old you may not have a ground(earth) connection(green or bare wire). My buddy sold his old house last year and he had to pay for an electrician to rewire his house. It had the old knob and tube wiring all through the house. ie 2 bare wires in the wall seperated by ceramic knobs and tubes where the wires passed thru walls. All of his electrical outles were 2 prong not 3. Take the cover off of an outlet and look inside you should see 3 wires a bare copper(earth) black ( hot) and neutral( white). Measure between all three. 110 between black and white, 110 between black and bare, zero or almost zero between white and bare.
 

Destroyer OS

Member
2005-11-14 11:09 pm
PNW
Way ahead of you buddy. Earth ground is the grounding of the conduit due to "updates" in the basement to allow a modern heating unit to regulate the steam system.

It is not proper earth ground and you are not posting any sort of relation to my question. As I said before I had to remove the neutral to earth ground filter because the earth ground is so poor that I got nothing but huge noise being fed back into the system.

Now I am wondering if I connected it back up but put a resistor inline with the neutral pre-filter, if it would then dump the noise into the conduit "earth ground". The challenge is that the resistor would have to be less than any given piece of equipments resistance and I am not sure if the value would be high enough.
 
I think the current UK regulations do not allow the conduit to act as the Earth.
There must be a direct wire link all the way back to the Earth on the distribution board. This PE link must be tested to prove it meets regulations before the system can be commissioned. The test involves a high test current and not exceeding a specified voltage drop.

The important part is the copper wire PE from every socket back to the distribution board. I think it is not allowed any joints that can deteriorate.

I am not an electrician, so much of this is from reading what is around.
You need a qualified electrician to check your system. He may recommend improvements or he may condemn it until it is repaired.
 
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Destroyer OS

Member
2005-11-14 11:09 pm
PNW
Right... I am pretty sure my landlords do not care.

The majority of sockets in the place do not have a three prong socket. A few do, and very few if any besides mine have it wired to the grounded conduit. (I installed a better socket and more in one location)

However I would like to point out my aims have little to do with the electrical system itself. Remember this topic is about preventing feedback and or burning off the attenuated signals.

Essentially I am wanting to either change the source of electrons for the attenuated signal or I want to flatten the signal. It matters not if it is changed from the 60hz it is now.
 
In the US EMT (Electrical Metal Tubing) conduit is a permitted method of grounding outlets. This is a lighter conduit held together with set-screws, there is also a heavy duty conduit with threaded pipe ends. In any case EMT will carry much more ground fault current than a wire. The rules get interesting if a ground wire is run in the conduit.
 
The conduit does not give 115/120v in my building.

Borrow a transformer? Yeah maybe... I am more interested in developing ways to attenuate then dissipate unwanted signal though at the moment.

That is what you are doing with an isolation transformer, massive attenuation. No need to dissipate it, why make work for yourself fighting a capacitive ground loop when it can be cut.
 
I am not sure I think isolation transformers are as good as you do.

Have you heard what filter capacitors do for noise? I am pretty no system with an isolation transformer has ever done nearly as much, at least that I have heard.

Plus the expense of the ones that can do any where near 15/20a is through the roof.
 

wakibaki

Banned
2008-01-08 11:51 pm
How about a battery?

You could have maybe 2. Charge one and run off the other one. Or solar + battery. You need to dimension the system so the worst case sunlight provides enough daily power for your daily listening. Then you can isolate yourself from the mains completely.

w
 
I have no desire to be off the mains.

A really good idea came up. How could I cancel the signal that is attenuated by feeding the same signal back on it?

One idea is to have two capacitors running in parallel but one is off 180 off phase so the merger of information after them will cancel all the noise.

Unfortunately two sets of capacitors would be very expensive, so I need to find a way to do that instantaneously for fluctuations, without buying another set of capacitors.

One other idea that I do not know about is what happens if you turn AC into DC, but the DC circuit is in series... what happens to signal once it is turned into DC? Could I bleed the signal after it becomes DC with something like a light bulb or speaker?

The only way bleeding the signal that is the attenuated information would work in series with the capacitors is if it somehow put out zero signal or only 60hz. A small isolation transformer might work for this. Unfortunately I think it would be expensive, very. The idea is good though because I do not want an isolation transformer as the source of power.

Lastly how big of a resistor would I need to put in parallel with the circuit that is for the power of the equipment so that the attenuated information will never want to ground through my equipment, as in it will see that network as higher resistance even though the equipment I have will not see the resistance. I think I will use one of these. resistors_mills_mrc
 

wakibaki

Banned
2008-01-08 11:51 pm
I have no desire to be off the mains.

That's an odd thing to say.

I thought you had a desire to listen to music uncorrupted by noise.

I offered a workable suggestion as to how it could be achieved. Either with or without using the mains.

If you don't like it, don't use it, but it'll work and it's simple, unlike your noise cancelling solution, which is not simple and may never work.

w
 
I am not sure I think isolation transformers are as good as you do.

Have you heard what filter capacitors do for noise?
I very much doubt that mains noise is your problem so filtering may not be a solution PSU filters do a good job of removing mains noise by converting it to DC. A filter capacitor may filter out the high frequency components of the noise you are hearing making you believe that you have a solution. If your problem is a ground loop then the isolation transformer used properly will fix it that is why I suggested borrow one to see if it fixes your problem.

An isolation transformer is useless as a mains filter is used primarily for breaking ground loops.

Go through the signal path on your equipment and ask yourself how is this noise getting into it?

Just out of curiosity what is the AC voltage between ground and the two lines? I don't know much about the US electrical system but in Australia any significant voltage between neutral and ground may introduce mains noise into the signal path

Try plugging all your equipment into one power board, using multiple outlets can be a problem especially if the building wiring is bad.

Plus the expense of the ones that can do any where near 15/20a is through the roof.
2.4Kw is a lot of power for an entertainment system especially in an apartment, try a 5 amp transformer for testing, it should handle the overload for 10 minutes check it after 5 minutes to see if it is getting hot.
 
This is one of the most unproductive threads ever. There is nothing to "fix" you take things as is where I live. The landlords are not going to do anything.

I only use X2 capacitors by the way, high voltage rating.

So the main question now is how do I invert the signal running in parallel to the capacitors?
 
This is one of the most unproductive threads ever. There is nothing to "fix" you take things as is where I live. The landlords are not going to do anything.

I only use X2 capacitors by the way, high voltage rating.

So the main question now is how do I invert the signal running in parallel to the capacitors?
The reason this thread is unproductive is because what you are asking for doesn't make any sense.