Phono stage picking up radio signals?

RE VH IC's: If the shield is only connected at one end, then it can't be carrying anything. The term "ground return" is sometimes used to mean the negative signal conductor.

You can mix shielded and unshielded in the same system if you want to.

I still advise you to try some inexpensive cables first, just to make sure that it really is the unshielded Nordost that is causing the problem. Cheap Monster, Audioquest, Straightwire, or MIT should do the trick.

There is no reason for a phono system to act as an antenna, even with a MM cartridge, with the possible exception that you live near or under a transmission tower, if you will:

1.) Make sure the turntable, tonearm, and phono preamp (if separate) are properly grounded to the rest of the system. If the separate phono preamp has a three prong plug, use a lifter (or "cheater plug") to disable the ground -- it gets its "ground" from the main preamp through the IC's.

2.) Use shielded IC's from the phono preamp to the preamp (and throughout your system, preferably) making sure the IC's have a "floating shield" (one that's connected to ground at only one end, usually the "arrowhead" end) and make sure the arrowhead end is at the preamp.

3.) Oh yes, and make sure the main preamp IS grounded at the wall!

That should do it.

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Clio09: Your preamp is OK running thru the RSA if the RSA is grounded. (And I'm assuming your wall receptacle ground is functioning?) Yes, do try removing the ground pin from the PS cord, however that's more for hum prevention, but still a good idea.

The Kuzma should also have a separate ground wire (bundled with the "fixed cable") that you can attach to the ground lug on the back of the Whest, or on the back of the main preamp. Ditto the TT, however, again, these are mainly for hum prevention. I was surprised to learn your Stogi came w/ a dedicated IC, but I've gotta believe it's high quality and shielded. And I don't think the Sota power supply is the problem.

Which brings us back to the IC's I honestly don't know anything about the Nordost Red Dawn cable topology (conductor layout/design) and a number of cable manufacturers make unshielded cables that still have arrows so you can always install them in the same orientation after break-in, so don't assume the Red Dawns are shielded. Check with Nordost.

A quick and dirty diagnostic for the Red Dawns is: while the problem is evident, touch one hand to a bare metal spot (like a screw) on the grounded preamp chassis, and with the other hand, grab both Nordost IC's, and see if the radio reception doesn't diminish. If it does, then they're the problem.

I've never tried a Ground Zero. I've always achieved "star grounding" by making my preamp the only component that was grounded thru its power cord. (Caution: don't work on amps or other components unless the IC's are in place or you've re-grounded them at the wall.) Again, this is a ground loop issue, and if your system has no or very little 60 cycle hum, then you don't have ground loop problems.

Clio:

1.) Re the Nordost claims: Bullpucky! (especially for phono use)

2.) A tube phono preamp is less susceptible to RFI because the signal is not physically coupled all the way through as with a SS unit.

3.) I wouldn't use both power conditioners on the same electrical (house) circuit. They could produce their own ground loop.

4.) I would ground the TT. There are several alternate ways to do this. The main thing is not to connect the phono preamp ground lug to the preamp ground lug. The best way would be to connect both the phono cable ground wire and a wire from the TT lug to the preamp lug. Alternately, you could connect the phono cable ground wire to the TT lug, and another wire from the TT lug to the preamp lug.

5.) As for shielded cable choices, a number of manufacturers make cables specifically for use as phono IC's, including Cardas, Hovland, XLO, Straightwire, and others. I'd just get some cheap Monster or old MIT 330's for a try.

Clio09: Sounds like the RFI problem was in the phono preamp. As for your question about the ground wires, yes you can connect them as you say -- just make sure the TT and the tonearm aren't electrically connected (no metal parts touching) or you will have created a ground loop.

And definitely try shielded cables.

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Clio09: "shielded on both ends" or "shielded on one end" is not the correct terminology. A shield, whether it's braid or foil (sometimes both,) encloses the cable from one end to the other.

If the shield is connected to the ground pin (in the case of power cords or balanced IC's) or to the outer ring (ground) of an RCA plug at only ONE end, it is said to "float" (at the end where it's NOT connected.) This is the best way. It's like putting a grounded box around the cable, but since it's only connected to ground at one end, NO CURRENT CAN FLOW THROUGH IT.

When shields are connected to ground at both ends, they still shield, BUT they also form a loop -- the other half of of the loop being the negative signal conductor inside the cable which, of course, is always connected at both ends (or you'd get no music signal!)

This loop acts like a kind of antenna (but usually not Radio Frequency, RFI, like radio stations) instead it picks up nearby Electomagnetic Radiation, EMI, usually 60 cycle, generated by power lines, power cables and transformers.

Many highend manufacturers sell their equipment with perfectly good shielded power cords. Unfortunately, UL approval requires that the shield be connected to ground at both ends (I don't know why) but this defeats the purpose from an audiophile standpoint! It's easy to fix though.

As for interconnects. It was Bruce Brisson (owner of the company that makes MIT cables) who originally put MonsterCable on the map with his "shotgun" interconnect design. It's called "shotgun" (double barreled!) because, unlike single ended IC's previously, which had a single + conductor in the middle, surrounded with a braided - conductor-cum-shield (coaxial, or coax), he used TWO signal conductors + and - (shotgun) inside, connected at both ends of course (to the RCA pin and ring), to carry the music signal, surrounded by a shield connected at only one end (the "arrowhead" end) which therefore carried no signal, but protected the internal signal conductors from interference. With a few exceptions (Kimber, Nordost, and a some others) this is the cable topology (conductor layout) used by most of the manufacturers today. Some, like Straightwire, even put a separate shield around each signal conductor and tie the two shields together and connect them just at the "arrowhead" end.

Now, this business about the "arrowhead." The reason it points to the (one) end where the shield is connected to ground, is so that if you point it in the direction of signal flow, the shield will be connected to ground at (usually) the preamp end. That is where the best ground potential (usually) is, and therefore the quickest, easiest "drain" for any interference the shield picks up. The exception, is the pre-to-amp interconnect, where if you've lifted the ground on your amp PC, you should point the interconnect arrow "backwards" to the signal flow (or toward the preamp) so that the shield is still connected to ground at the preamp end. (Notable exceptions to this convention are Purist and Magnan, but they have unconventional topologies.)

I could go on, but your eyeballs are probably falling out by now, so I'll quit. Let me know if you have any questions :~))

Neil

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Zargon, thank you. There are some cable manufacturers who, especially in their speaker cables (which aren't ever "ground shielded",) orient their arrow direction based on "wire draw." Which simply means the direction the wire was pulled through the dies during manufacture. Supposedly, the orientation of the metal crystals as a result of the drawing process makes it easier for the electrons to flow in one direction than the other.

Others who produce spkr. cables and IC's which are symmetrical as far as orientation goes, often include arrow
indications so that (according to them anyway) you'll be able to orient the cables in the same direction, should you have to remove and re-install them after they've been broken in. Personally, I think it's just a "me too" marketing ploy.