"Hello, as already mentioned in my introduction, I am inexperienced but use the soldering iron for basic tasks, like soldering RCA connectors, etc. Well, I bought a used Tricord Dino phono preamp to connect it to my Rega Planar 2 turntable. As you know, Rega turntables share the arm ground with the left channel. This turntable uses a very cheap direct cable from the arm to the phono preamp. I wanted to modify this cable by cutting it and mounting a metal box under the turntable with female RCA terminals so I could choose the cables based on construction or length. Now, when I turn up the volume without music, there is a hum coming from the speakers. If I touch the box, the hum increases, and it also increases if I touch the arm. The RCA connectors do not come into contact with the metal box. I think I’ve created a ground loop; how can I fix it? Should I connect the left and right negatives to the metal box? Should I connect the metal box to the negative terminal of the phono preamp?
I don't have any photos, I'll take them this evening but I discovered something rather strange... I use dynaudio xeo amplified speakers and if I insert the CD player cables the ground loop disappears.
What's the right wire, it's ground tonearm connected to xassis? If you use Rega disconnect from xassis & connect to left ground output RCA as Rega did & done.
That's exactly the point: if I connect the ground wire to the phono preamp and to the RCA box (which has no contact), the hum decreases. If I move my hand close to the tonearm, it acts like an antenna. But if I touch the ground wire with my fingers, everything stops—the tonearm no longer acts like an antenna, and the hum almost disappears. No matter where else I connect the ground, I don’t get the same effect, just a slight reduction in hum. I don’t get it… do I have to stay attached to the ground myself? 🙂)
Sounds as though you are acting as a ground when you touch the wire! To 'replace yourself', try connecting the ground wire to something that is itself grounded, so it connects to your electricity supply's ground. However, just plugging the wire into a power socket's ground terminal is not advisable, and could be dangerous.
The ground terminal on your phono preamp probably isn't sufficient, especially if it has an external power supply, e.g. a 'wall-wart'.
The ground terminal on your phono preamp probably isn't sufficient, especially if it has an external power supply, e.g. a 'wall-wart'.
Yes, I become the ground eliminator myself, but none of the components I have have a ground terminal on the socket, nor on the chassis—not the Dynaudio Xeo, not the Rega power supply, nor the Trichord Dino phono preamp. Well, I've solved the mystery... wow! All the components have two-pole plugs, so no ground, but the CD player does. As a result, when I connect the CD player, it provides the ground reference that breaks the loop. To avoid hearing hum, I'll have to keep the CD player connected forever. I don't think it's advisable to add a ground to my components that originally don’t have one... or could it be done?