How essential is shielding?

"What are your thoughts on (Synergistic´s) active shielded cables?"

Very high tech and very expensive.

I'd have to hear them to make any value judgement.

Personally, I prefer an effective shielding approach that is not active, like mu metal, which I already use to good effect to shield my phono step-up device and ICs from external noise inducing EM fields.

FWIW my Audioquest CV6 speaker wires use a similar but lower tech and cost active approach with their DBS devices. These speaker wires are very good but I have not been able to determine how much DBS has to do with it.

Of course, low level ICs and speaker wires are two different beasts as well to start with.

Hasse, Active shielding means placing buffered common mode signal back on the shield thus reducing capacitance and therefore pickup. It is technique widely used in low level amps like EKG amps but Synergistic's definition is different. They just claim putting battery on the shield. Battery with high voltage is used by Audioquest to polarize dielectric (dipoles) and make it sound the best even if not used for a while (no break-in). Synergestic is a little vague on this.

What are your thoughts on (Synergistic´s) active shielded cables?

Hasse - I owned Synergistic's top-of-the-line Apex interconnects for a few months. At least for me, Synergistic's active shielding worked as advertised. With the Apex cables in the system, backgrounds became spooky quiet.

I didn't keep them because, in my system, they didn't have a natural tonal balance. Of course, YMMV.

Bryon

"It is worth to mention that EMI pickup of lower frequencies such as approx 500kHz generated by many class D amps can be picked-up as direct connection thru capacitance (important to keep wires apart or right angle) and not thru the electromagnetic pickup"

I wonder if this accounts for the intermittent low level high pitched whine I get on occasion with DNM Reson ICs from ARC tube pre-amp to BC ref1000ms? The pitch seems to change with exact location/orientation of the ICs. Not sure if position of the two ICs relative to each other is the determining factor or not.

I switched in a pair of MIT ICs with network boxes the other day and that appears to have eliminated the noise issue for now. I'm waiting to see if it continues in that the issue has come and gone mysteriously in the past for no clear reason.

I once had problems with noise in my phono system so I ended up bringing my table to the dealership. At the dealer, the noise problem did not occur, but, the dealer noted that the phonocable was unshielded. He had a cable that was supposedly identical, except that it was shielded (both made by Kimber). It turned out that the shield cable solved the noise problem. I asked the dealer why he sold me the table with the unshielded cable, and we ended up doing a comparison. The unshielded cable sounded better--more open on top, and greater ease in hearing subtle detail. He said he always starts with the unshielded cable and only goes to shielded when noise intrudes.