Sheilded/Unsheilded Power Cords

Honestly, when I was done braiding the wire and all the mess, the DIY were going to be better...No matter what :).

I had not a/b the cables, until just before this reply. "more noise" between the two- nope. Seems to be the same. I had meant this for another post, how much noise is too much? The old crank the volume and stick your ear up to the tweeter, I do here a little noise. Not heard from the listing position, but can hear with my ear on the tweeter. Not sure really how to put this into words. The tuner will bleed into the next/nearest analog input. $6000 bucks for bleeding inputs, huh.

On the flip side the "dynamics" seemed improved with the shielded DIY's. The highs seem higher and the lows seem fuller. Interesting...

The amp circuit to the wall is unshielded, all runs in the room are shielded. The source circuit is actually shielded all the way to the breaker panel. I use balanced ic where possible, from the processor to the amp. With HT, one seems to have a few more devices, which seem to add more possible problems.

No, the existing ROMEX are not shielded. That's the reason a normal person would buy the live lead finder pen(I gotta find out this thing is really called), to find these lines. My equipment is also not placed directly up against a wall, next to these lines.

Please explain what "unwanted capacitance" means. Is this the ability of the wire to store a charge.

Also the power conditioners in the system are a ps ultimate outlet ran into a Richard Gray 400. Really weird part with out the power conditioners, the buzz is 75% louder, plain as day. What I would call very bad. With the ps, same. With the "noisy" RGPS, very quiet. Funny, exactly the opposite of what I would have thought.

I hope I am not describing a long winded minor ground loop hum. This was not the purpose of the thread. This background noise is very minor.

Learning something new every day,

Thanks all
Marty

Audioengr: Sorry to step on your toes, but thanks for proving my point. Your line of questioning to Marty just goes to show that even those that i consider to be "worthy" and design / manufacture PC's think of them as nothing more than "an extension cord" ( hypothetically speaking ).

While you have a point about what happens upstream from the PC, you also have to take into account several other factors:

1) One can piss anywhere along the river that they want. So long as the contents of the river are highly filtered prior to delivery to the water fountain, i don't care what takes place. In effect, one could use unshielded wire for a few million miles. This would in no way reduce the effectiveness of a well designed filter at the end of the wire.

2) Why is it that most engineers / designers / manufacturers have such a hard time thinking of a power cord as being anything more than a "conduit for power delivery" ? Aren't the internals of a PLC made up of capacitors, inductors ( which is nothing more than wire or wire on a former), resistors, diodes, impedance altering devices, etc.. ??? What would stop someone from applying filter technology and the associated componentry to a power cord design ?

3) The fields generated by the in-wall wiring are not anywhere near as close to the low level signal carrying cables and components as the power cords are. Therefore, EMI and radiation from the in-wall wiring is far less critical.

4) Stop thinking of a power cord as an extension cord and start thinking of it as a part of the power supply.

Sonic Genius: Your comments apply only to designs that are made by those "thinking within the box". If you were to step outside of the "box", you might begin to see how those factors could be reduced or even put to use as a positive aspect of the design. Certain design attributes are only "negative" when you can't control them or they are not taken into account for. When it comes to AC, signal manipulation is the name of the game. Sean
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On the flip side the "dynamics" seemed improved with the shielded DIY's. The highs seem higher and the lows seem fuller. Interesting...

This may be true, but it is difficult to attribute this to the shielding. The new cables were likely lower capacitance or lower inductance as well.

Please explain what "unwanted capacitance" means. Is this the ability of the wire to store a charge?

Yes, but it also contributes to a low-pass filtering effect when installed in the system. Creates an impedance to high-frequency currents.

I hope I am not describing a long winded minor ground loop hum. This was not the purpose of the thread. This background noise is very minor.

It seems to quack and look like a duck....

Sean - No offense taken.

Why is it that most engineers / designers / manufacturers have such a hard time thinking of a power cord as being anything more than a "conduit for power delivery"

I can only speak for myself. A power cord is just one segment of a longer power transmission circuit, which can be described as series resistance and inductance and parallel capacitance. However, the catch is whether this is described as a lumped parasitic or a distributed set of parasitics, like a transmission-line. The former is used at low frequency and the latter at high-frequency. The debate goes on ...

Aren't the internals of a PLC made up of capacitors, inductors (which is nothing more than wire or wire on a former), resistors, diodes, impedance altering devices, etc.. ??? What would stop someone from applying filter technology and the associated componentry to a power cord design ?

Nothing. You can get filtering effects from different power cord constructions or just add filtering elements to the cord, such as inductors, ferrites, resistors and caps.. I do not happen to believe in filtering in PC's myself, except for the ground wire. This can be useful to minimize noise from ground-loops.

Stop thinking of a power cord as an extension cord and start thinking of it as a part of the power supply.

I agree. Certainly is a part of the power system. As is the transformer on the pole and the transmission lines that deliver to that. However, the further that you get from the component, the effects of the component load on the system become smaller and smaller because the impedance of the source gets increasingly lower. At some point, you ignore the effects because they are second-order. I have chosen this point to the be power panel in the house. This causes a small error in any calculations of power delivery.

Radiated power drops rapidly with distance. No need to shield Romex in wall. It's too far away from the system.

The power cord, which is the last 6' of the power delivery system, seems to be an ideal place to put a tuned filter. Filtering out everything but the pure 60Hz using a power conditioner and a tuned power cord would seem to be optimal.

It seems that shielding on a power cable would keep it from radiating noise to the high impedance lines, such as the IC's. If the power has high frequency noise, it may radiate this too. Shielding is a difficult design process, however. No doubt many manufacturers just use trial and error.

Just my 2 cents (or maybe 3).