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Hi,

> I still dont understand why shields do not screen from rf ?

They do screen from capacitive coupling, but not from magnetic coupling. Radiowaves can be fun, resonance effects are usually present in arials and all sorts of other stuff, so a certain part of the radiation is screened, just as capacitive coupling of hum is screened.

My main point was that screening a cable or not does not provide a reliable indication of good engineering nor doees it indicate from hum & noise.

For example you can use unscreened wires at moving coil cartridge levels with no hum whatsoever (we are talking about 0db = 250uV, that is 80db less signal that the output from a CD player BTW), AS LONG as the two conductors are extremely tigtly twisted to reject Hum fields.

Screens in interconnects probably hark back in the days of the old Valve Systems where the output impedance of a preamp could easily amount 100KOhm + and the input impedance of the power amplifier may be over 1 Megaohm, a situation which would make capacitively noise around 60db higher than for a modern system using otherwise identical unscreened cables.

> As far as ferrites are concerned , they only work for a
> small range, so how would that help ?

Again, this depends heavily on the formulation of the ferrite

> And I also want to know why interconnects sound different
> when plugged in reverse ?

They do? You observed this? I mean not cables that have a screen tied only to one side of the cable, but absolutely symmetrical cables?

> Why do they have to be burnt in for upto months to start
> working as intended ?

Do they? You observed this yourself?

It can be demonstrated that conductors change when moved and when current flows. A process called quantum tunneling can help to make layers of impure metal at the crystal boundaries "porous" to electron transfer.

As AC signals travel in a conductor not actually as current flow IN the conductor, but as EM wave surrounding the conductor (see Maxwell et al) a localised disruption of condcutivity (crystal boundary) may cause a disturbance to the wave, it may do so of course only when it coincides with a "peak" in the waveform, meaning it's effects appear random and tend to be averaged out with steady state test signals, but maybe not with music.

I do not know if this effect is audible. I would not claim with any authority that cables show significant burn in, but several physical mechanisms exist that MAY under certain circumstances very well be audible.

May I ask why you must formulate your questions so extremely confrontational? You state conjecture as fact and demand explanations for them. A Secret Policeman may try such tactics on a suspect to rattle him, I think in this forum a more civilised approach of attaining illumination on the various subjects (or not, as such may be) will get you much better responses.

Ciao T

<blockquote data-quote="3DSonics" data-source="post: 640659" data-attributes="member: 1907">Hi,&gt; I still dont understand why shields do not screen from rf&nbsp; ? They do screen from capacitive coupling, but not from magnetic coupling. Radiowaves can be fun, resonance effects are usually present in arials and all sorts of other stuff, so a certain part of the radiation is screened, just as capacitive coupling of hum is screened.My main point was that screening a cable or not does not provide a reliable indication of good engineering nor doees it indicate from hum &amp; noise. For example you can use unscreened wires at moving coil cartridge levels with no hum whatsoever (we are talking about 0db = 250uV, that is 80db less signal that the output from a CD player BTW), AS LONG as the two conductors are extremely tigtly twisted to reject Hum fields. Screens in interconnects probably hark back in the days of the old Valve Systems where the output impedance of a preamp could easily amount 100KOhm&nbsp; + and the input impedance of the power amplifier may be over 1 Megaohm, a situation which would make capacitively noise around 60db higher than for a modern system using otherwise identical unscreened cables.&gt; As far as ferrites are concerned , they only work for a &gt; small range, so how would that help ?Again, this depends heavily on the formulation of the ferrite &gt; And I also want to know why interconnects sound different &gt; when plugged in reverse ?They do? You observed this? I mean not cables that have a screen tied only to one side of the cable, but absolutely symmetrical cables?&gt; Why do they have to be burnt in for upto months to start &gt; working as intended ?Do they? You observed this yourself?It can be demonstrated that conductors change when moved and when current flows. A process called quantum tunneling can help to make layers of impure metal at the crystal boundaries &quot;porous&quot; to electron transfer. As AC signals travel in a conductor not actually as current flow IN the conductor, but as EM wave surrounding the conductor (see Maxwell et al) a localised disruption of condcutivity (crystal boundary) may cause a disturbance to the wave, it may do so of course only when it coincides with a &quot;peak&quot; in the waveform, meaning it's effects appear random and tend to be averaged out with steady state test signals, but maybe not with music.I do not know if this effect is audible. I would not claim with any authority that cables show significant burn in, but several physical mechanisms exist that MAY under certain circumstances very well be audible.May I ask why you must formulate your questions so extremely confrontational? You state conjecture as fact and demand explanations for them. A Secret Policeman may try such tactics on a suspect to rattle him, I think in this forum a more civilised approach of attaining illumination on the various subjects (or not, as such may be) will get you much better responses.Ciao T</blockquote>

[QUOTE="3DSonics, post: 640659, member: 1907"] Hi, > I still dont understand why shields do not screen from rf ? They do screen from capacitive coupling, but not from magnetic coupling. Radiowaves can be fun, resonance effects are usually present in arials and all sorts of other stuff, so a certain part of the radiation is screened, just as capacitive coupling of hum is screened. My main point was that screening a cable or not does not provide a reliable indication of good engineering nor doees it indicate from hum & noise. For example you can use unscreened wires at moving coil cartridge levels with no hum whatsoever (we are talking about 0db = 250uV, that is 80db less signal that the output from a CD player BTW), AS LONG as the two conductors are extremely tigtly twisted to reject Hum fields. Screens in interconnects probably hark back in the days of the old Valve Systems where the output impedance of a preamp could easily amount 100KOhm + and the input impedance of the power amplifier may be over 1 Megaohm, a situation which would make capacitively noise around 60db higher than for a modern system using otherwise identical unscreened cables. > As far as ferrites are concerned , they only work for a > small range, so how would that help ? Again, this depends heavily on the formulation of the ferrite > And I also want to know why interconnects sound different > when plugged in reverse ? They do? You observed this? I mean not cables that have a screen tied only to one side of the cable, but absolutely symmetrical cables? > Why do they have to be burnt in for upto months to start > working as intended ? Do they? You observed this yourself? It can be demonstrated that conductors change when moved and when current flows. A process called quantum tunneling can help to make layers of impure metal at the crystal boundaries "porous" to electron transfer. As AC signals travel in a conductor not actually as current flow IN the conductor, but as EM wave surrounding the conductor (see Maxwell et al) a localised disruption of condcutivity (crystal boundary) may cause a disturbance to the wave, it may do so of course only when it coincides with a "peak" in the waveform, meaning it's effects appear random and tend to be averaged out with steady state test signals, but maybe not with music. I do not know if this effect is audible. I would not claim with any authority that cables show significant burn in, but several physical mechanisms exist that MAY under certain circumstances very well be audible. May I ask why you must formulate your questions so extremely confrontational? You state conjecture as fact and demand explanations for them. A Secret Policeman may try such tactics on a suspect to rattle him, I think in this forum a more civilised approach of attaining illumination on the various subjects (or not, as such may be) will get you much better responses. Ciao T [/QUOTE]

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