Preamp-Tonearm Grounding Problems?
Can someone HELP?
I am having two problems with my phono section and wonder if someone might be able to help.
The Problems are as follows.
1. No matter what type of tonearm cables I use the tonearm itself is "hot" (touching any bare metal to it pops like crazy) and gives off static discharges that cause pops and cracks either during idle or LP playback. Grasping the underside of the arm on a metal surface stops most of the discharges but not all. In fact I can feel a slight current sometimes when I do this.
2. In tracking down a ground loop as the cause for #1, I found that if I disconnect the tuner either from the preamp or the in-wall antenna connection, dependiing upon which tonearm cables I use I get a "flutter" noise through the phono section either by holding/grounding the tonearm or not.
As far as #1 is concerned, I realize I am acting as a new "ground" by touching bare metal to the tonearm or by grasping the underide of the arm, which stops most of the discharges. I was assuming a ground loop effect from within the system but the only thing I can determine is that unplugging all other cables from the preamp and removing all other AC power cords from the wall does not help.
As far as #2 is concerned, I am not sure if this is related to #1 but I disconnected the outside ground wire of the antenna from its ground post, which is not at the mains ground post, and there is no change in either #1 or #2.
It has been a major source of frustration since tracking it down has taken a long time and considerable inconvience. I have been trying to determine the cause since, 11/99, when I upgraded my TT/arm/cart all at once. Since I did not have the exact problem with my old set up
I automatically assumed it was in the cart. or arm.
I remember checking the new arm in the past for the same issues showing now and do not remember it being the problem. The fact that the dealer I am using is in, San Jose, CA., and I am in, Seattle, WA. does not help, as well as my scant electronics background.
What would cause the arm to be "hot" like it is? It seems like it is a preamp grounding issue now. I have the ability to use phono cards within the preamp, or separate phono cards in a separate case outside the preamp which is powered by the preamp's own separate power supply and utilizes a dedicated inputs in the preamp, or a third party phono stage which utilizes a line stage input and all the same problems take place.
I swapped out my preamp with another one of the same and had the same problem. My amp/preamp are NAIM gear and use "star" grounding, which I do not totally understand, could this be part of the problem? Someone mentioned measuring ground potentials before, do you think this may be the problem? My Ac panel uses a grounding rod as its "ground". I went around and un-hooked all other ground wires on the cold water pipes but no change. I have three separate outlets to use, two are separate 20 amp dedicated lines and the other is the original house circuit. I had the two dedicated lines installed to minimise EMI problems in the phono stage, but it only helped a bit. Plugging the amp/preamp into either the original outlet or one of the dedicated outlets, while unplugging all other items does not alter #1 or #2.
What now? I would really appreciate any advice! This has really ot me frustrated since I can hardly enjoy LP's since 11/99.
Thanks.
Gerard
[email protected]
I am having two problems with my phono section and wonder if someone might be able to help.
The Problems are as follows.
1. No matter what type of tonearm cables I use the tonearm itself is "hot" (touching any bare metal to it pops like crazy) and gives off static discharges that cause pops and cracks either during idle or LP playback. Grasping the underside of the arm on a metal surface stops most of the discharges but not all. In fact I can feel a slight current sometimes when I do this.
2. In tracking down a ground loop as the cause for #1, I found that if I disconnect the tuner either from the preamp or the in-wall antenna connection, dependiing upon which tonearm cables I use I get a "flutter" noise through the phono section either by holding/grounding the tonearm or not.
As far as #1 is concerned, I realize I am acting as a new "ground" by touching bare metal to the tonearm or by grasping the underide of the arm, which stops most of the discharges. I was assuming a ground loop effect from within the system but the only thing I can determine is that unplugging all other cables from the preamp and removing all other AC power cords from the wall does not help.
As far as #2 is concerned, I am not sure if this is related to #1 but I disconnected the outside ground wire of the antenna from its ground post, which is not at the mains ground post, and there is no change in either #1 or #2.
It has been a major source of frustration since tracking it down has taken a long time and considerable inconvience. I have been trying to determine the cause since, 11/99, when I upgraded my TT/arm/cart all at once. Since I did not have the exact problem with my old set up
I automatically assumed it was in the cart. or arm.
I remember checking the new arm in the past for the same issues showing now and do not remember it being the problem. The fact that the dealer I am using is in, San Jose, CA., and I am in, Seattle, WA. does not help, as well as my scant electronics background.
What would cause the arm to be "hot" like it is? It seems like it is a preamp grounding issue now. I have the ability to use phono cards within the preamp, or separate phono cards in a separate case outside the preamp which is powered by the preamp's own separate power supply and utilizes a dedicated inputs in the preamp, or a third party phono stage which utilizes a line stage input and all the same problems take place.
I swapped out my preamp with another one of the same and had the same problem. My amp/preamp are NAIM gear and use "star" grounding, which I do not totally understand, could this be part of the problem? Someone mentioned measuring ground potentials before, do you think this may be the problem? My Ac panel uses a grounding rod as its "ground". I went around and un-hooked all other ground wires on the cold water pipes but no change. I have three separate outlets to use, two are separate 20 amp dedicated lines and the other is the original house circuit. I had the two dedicated lines installed to minimise EMI problems in the phono stage, but it only helped a bit. Plugging the amp/preamp into either the original outlet or one of the dedicated outlets, while unplugging all other items does not alter #1 or #2.
What now? I would really appreciate any advice! This has really ot me frustrated since I can hardly enjoy LP's since 11/99.
Thanks.
Gerard
[email protected]