are you using unshielded ICs? |
I had the same problem (do a search in Audiogon). I was able to stop the radio station by using shielded interconnects, ferrite clamps and switching phono stages. This was a very annoying problem for me and I was close to giving up on vinyl all together and switching to digital. Good luck. |
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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Thanks for the suggestions. Here is my set-up currently:
I have a Kuzma Stogi tonearm with a "fixed" cable that is grounded at the Whest.
I am using a Benz M2 MC cartrdige.
I'm using Nordost Red Dawn cables as my standard IC for all components, including the Whest. I suspect they are shielded at one end, the one with the arrow which is the end I plug into the preamp. The Whest also came with it's own ICs that I will try as well.
All my components are plugged into a Running Springs Audio Haley, which is then plugged into the wall. The RSA is in a continuous "on" funtion as it has no power switch of its own.
The Whest has a PS Audio Statement connected to it with removable ground pin. Right now the ground pin is in, but I will try removing it versus using a cheater plug.
Nsgarch - would you still recommend the preamp be grounded at the wall based on this? Also, my turntable is a SOTA with a separate power supply. Can you suggest how I can ensure it is grounded properly.
Lastly, I have a Ground Zero which I have not hooked up yet. Would this potentially clear up the situation. |
Okay, I referred to the previous thread on this posted by Rich62. After some testing here is what I have come up with:
Changing the ICs on the Whest makes no difference.
Unplugging the TT power supply from the RSA and the power supply umbilical from the TT makes no difference.
Additionally, when the above is done in conjunction with either leaving the tonearm cable and ground attached to the Whest or removing them does not remove the noise, although when the tonearm cable and ground are removed the noise is reduced.
Removing the ground pin from the PS Audio Statement that is connected to the Whest does not make a difference.
I have a PS Audio P300 lying around that the RSA replaced and read a post where someone said that may work so I'll try hooking the Whest and maybe my TT into it. Also, I'll try hooking up the Ground Zero. Before I do that, I am going to reconnect my Cary PH-301 and see if it has the same effect. I recall some noise from the Cary, but never heard a radio station before.
I am getting to the point where Rich62 was in his efforts. This is entirely frustrating and to make matters worse I don't have any flexibility to move equipment around. |
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. |
Nsgarch,
Thanks for the advice. The TT does not have its own ground cable, but it does have a ground lug under the chassis. I imagine it is for the tonearm cable ground wire. I prefer attaching the ground to the phono stage instead. My preamp is a Cary SLP-98 which is offered as a linestage or with a phono stage. Since I only have the linestage the RCA inputs for the phono section are plugged, as are the tube socket holes on the top of the chassis. However, it also has a ground lug and I wonder if I should try connecting the ground for the tonearm cable there as well. Probably can't hurt. |
Those interconnects have to be shielded or else yau can start enjoying radio while you listen to records. BTW any problems with clicks and pops? |
Nsgarch,
As for the Nordost cables they are not shielded according to what I found on their website. They have also provided a reason as follows:
"The use of flat cable geometry coupled with very precise conductor spacing alleviates the need for conventional shielding. In addition, the use of extruded Teflon provides better shielding than conventional insulation techniques. Nordost cables are not shielded because shielding increases the capitance of the cable by a factor of 55% or more when applied in the conventional manner. If the capacitance of the cable is increased high frequency information is rolled of and you don't hear all of the musical information."
Not sure if this is a proper explanation or if it is contributing to the problem as you indicate, but the P300 didn't solve anything and now I'm going back to the Cary to compare.
I'll post an update and in the meantime post a thread for suggestions of shielded ICs. |
Hooked up the Cary PH-301 which has 3 x 12AU7 and 2 x 12AX7 for tube compliment and while its noisy (hiss and some static) there is no FM or other radio interference that I can tell.
I'm at a loss at this point. More suggestions are welcome if any one can think of anything. Thanks |
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. |
Nsgarch,
Thanks for the comments. I have one question. Can I connect a wire from the TT lugnut to the phono preamp lugnut, then connect the tonearm cable ground wire to the phono preamp lugnut as well? |
Here is one question I asked the constructor of the Whest PS.20, James Henriot, before I bought the unit:
I have heard some rumours that the PS.20 is sensible to RFI signals.
Since I sometimes have problems with radio signals, I just wonder if this is correct.
Henriot's answer:
The rumours are right but we rectified the problem about 4 months ago and it was found that our loading supplier made the plugs incorrectly.
This was one month ago, and I have had no RFI problems with this unit. |
The unit I have was manufactured in March 05, so I probably have one of the units you are referencing. I will probably ask him for a new set of plugs based on this to see what difference they make. Thanks for the information. |
I am not familar with your phonostage so this reply may be redundant but if it has tubes try replacing them.
Some tubes play radio stations and others don't I don't know why but thats the way it is.
If that doesn't work then you have a grounding problem in your arm or shielding problem in your system somewhere.
One thing you can try is installing ferrite beads over the inputs of the phono. They must be inside the preamp to be effective. They don't work went put inside interconect RCA's. |
Kel34,
Thanks for the response. It so happens the tube phono stage works fine (Cary PH-301), it's the solid state one that is causing problems. I am looking into ari-hell's suggestion as that is the cheapest way to go for now. If that doesn't work I'll try a pair of shielded ICs, as Nordost are not shielded. If all that doesn't work I have two more phono stages coming that I was going to compare against the Whest and if they work then the Whest is pobably out and I'll choose between the Hagerman and Decware. |
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.
. |
Clio09 - Shoot James Henriot an email. He is a very nice guy who is very informative about his product. I think I have heard there was a batch that was shipped that was missing a part in the loading plugs that go into the back of the unit that was causing this radio reception/interference.
Shoot him an email with your serial # and problem, and see if perhaps you got a unit that had those issues...
good luck and keep us posted please. |
Audiofankj,
I have emailed James before and he has always responded in kind. I did email him about the RFI issue and given the fact that he is 8 hours ahead of me and it's the weekend I'll look for his response Monday. Also, I plugged in the phono stage without any load resistance plugs and it still picked up a radio signal. While the plug theory makes sense I'm at a loss as to why the unit would continue to exhibit the problem without the plugs being utilized.
I have also tried to work through he dealer who I bought this unit from (used) and he was somewhat helpful, but insists it is a problem with my tonearm cable or the position of the unit. I know it is not the tonearm cable as I've done many tests, and as for position, I only have so much room to manuever and nothig has worked do far.
Hopefully James will have an answer. |
Nsgarch,
I was seeking out shielded ICs and referred back to one of your posts. You mentioned a floating shield, meaning the IC is shielded on one end only. I have seen some double shielded ICs which are shielded on both ends. I'm assuming this won't work based on your post but was curious as to why.
Thanks |
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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Neil,
Thanks for the explanation. I was looking at the VH Audio Pulsar ICs and according to Chris Ven Haus in addition to being grounded at one end, the shield is also carrying the ground/return. So if I understand your explanation correctly this would not be the best method as it is not a floating shield.
I'll take a look at some of the other recommendations you have made for cable vendors. Could there be a situation where using floating shield ICs on the phono stage will require using them throughout the system? I'd like to just make this one replacement and be done with it.
Thanks,
Tony |
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. |
Neil, great explanation of "shotgun" topology, and the purpose of the "arrowhead". Most people I know think the arrowhead indicates the directionality of interconnects caused by the grainular structure of the conductor. You have cleared it up. |
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. |
I received an email response from James Henriot. It seems there is a modification for the Whest PS .20 for areas with high RF. The modification is now standard on new models of the phono stage sold in the US and Canada. James Henriot from Whest and Bob Leitz at the Analog Shop, where the unit was purchased, have been tremendously helpful and Bob is very much interested in making me a satisfied customer, even though this unit was technically purchased used. I also appreciate all the responses here on this thread, especially Neil who surmised the problem may actually be in the phono stage itself. I've learned a lot here about the various types of noise that can creep into a system.
I'll need to send the unit off, most likely to Mitch Singerman who services these in CA (close to me at least), but I'll post a follow-up when it gets back to me. I'm also going to wait on the cables until it does come back. |
There is a lot of necessary missing information in this thread.
A SPG, Single Point Ground is NOT a shield, it is an antenna and DOES put current in the "shield" that is now just a "wire" at this point. How do you think SPG works? CURRENT flows from the infinite open end to ground, thus current flows. A true shield NEVER, EVER has significant current flow. A SHIELD attenuates NOISE from inside to outside, or outside to inside (it works BOTH ways) as a RATIO, in dB, voltage. We should see virtually ZERO current.
FIX YOUR GROUND BUS!
If you use SPG, you won't die, but you are trading SIN for antenna coupled noise. BOTH are WRONG to accept as ideal as BOTH add CURRENT to the shield!
A lifted ground system with multiple lifted shields injects noise INTO the poor resistive differential (highest point to lowest point) ground system. As the ground is worse, the POTENTIAL difference from the end of the SPG ground point to the "ground" gets worse, aggravating the problem even more. Where is all that RF going? How is it getting there? What is it that current path parallel to? Maybe one SPG won't be an issue but many SPG added to a compromised ground will push it over the edge.
A SPG is trading off adding capacitive coupled RF noise injection into the core wires under the "shield" for removal of current induced SIN, Shield Induced Noise, from a poorly grounded system. A true shield has zip real current flow as the GROUND is at the same potential everywhere, or should be. By definition a ground at the exact same potential everywhere can't flow ground loop current.
A good shield will shield BOTH ingress RF and egress SIGNAL from a cable. That's what you want. Yes, our internal signal from digital devices needs to be SHIELDED from getting out of the cable as much as RF needs to be kept out. SPG "leak" RF into the exterior of the cable out as much as let it in.
One point to understand, is that the issues of a bad ground are superposition driven. As you "lift" a bad ground point and increase the resistance it looks more and more like an antenna, and less and less like SIN, Shield Induced Noise. They happen at the same time.
Once you REMOVE a ground point at either cable end for infinite resistance and thus no SIN current, we stop the SIN noise and fully replace it with Antenna coupled noise. A true SHIELD has ZERO current flow through it and is an ATTENUATOR. Making a SPG an antenna to stop SIN shield current isn't what best practice had in mind!
The ideal transfer impedance of the shield "R" times the shield current is the Voltage. Voltage equals current (should be near zero) times the transfer impedance at that frequency. But, when we have a bad ground our "R" goes far higher. Volts is current times resistance so that voltage product goes up as our shield tries to reach neutral state and flows current to the lowest potential spot in the system...where ever it is.
The ideal shield has the SAME resistance (zero) everywhere, same as a good ground and thus NO current potential to flow! It is all the exact same "spot" so current can't flow from HERE to THERE in the same spot. It can when here and there are DIFFERENT resistances relative to ground. This is why shields are rated based on their Transfer Impedance at specific frequencies. How LOW does the resistance look along the shield? Any "wire" will create a ground differential at frequency, so the right shield has to be used.
We can CHANGE the reference voltage from zero to ABOVE ground if we want to, but that EXACT voltage can't "move" or we again create a ground differential. We can have a one volt signal referenced to a million volts with a million and a ONE volt signal. This is still one volt potential difference UNTIL the signal reference point changes up or down. Usually we use something lose to EARTH ground for signal ground, not always. Connecting a SIGNAL ground to EARTH ground can mess this reference up. Make sure the circuit's "lowest potential" spot is understood. It may not be EARTH.
It is hard to remove a shield on an already built cable, true. So lifting a ground may be the better of two BAD situations. That's agreed to, yes. But we have to understand that it is WRONG from a SHIELD standpoint.
Many SPG systems with poor grounds worked better when the SPG were REMOVED and replaced with UNSHIELDED cable! This at least doesn't add noise to the ground bus and, XLR cables of good design can mitigate external noise passively with CMRR built-into the design. Try a UTP balanced cable and see what works. Many XLR have PIN 1 ground issue, too, so be aware of that. No, it isn't "earth" ground but "signal" ground. And yes, PIN 1 can cause SIN noise if they are too far apart in DCR.
NEVER, NEVER, EVER remove a safety ground!!! Now the fault current finds it path to ground through YOU! Touch a faulty unit with a "hot" chassis and guess what? Touch the next GROUNDED device and current goes through YOU. Sometime we learn a lesson ONCE and can repeat it to the angle at the pearly gates. This just tells you you need to FIX your ground, not make it a death trap instead.
Best, Galen Gareis
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