Have had a good look at this problem and, while I agree that some of the cheaper power supplies can make noise more of a problem, installation is the core issue.
A few things to do.
1. Mains Power Supply Cables
Use proper 240V three core flex for your incoming 240V AC mains supply connection and make sure the earth is connected to the earth terminal on the power supply. You need this for both safety and to ground the power supply housing. Generally the internal OV side of the DC power supply will also connect to this ground terminal internally via a resistor so the ground is necessary to stop your power supply voltage floating and acting as a high voltage aerial.
2. DC Supply Out Cables
Most of the DC supplies used for low voltage lighting are are 5V, 12V or 24V DC. The current used depend on what lights you are driving but select cable which is big enough to handle the maximum current and to minimise voltage drop. I recommend for most people to use the figures 8 cable which is used for 12V garden lights (use the thickest one in your Bunnings or other store). Typically this will be 2.5 mm2 copper cross section per wire. Have seen so many people posting about using 0.5 mm2 cables etc but these are far too small and you just create problems for yourself with voltage drop....result dim lights!
Where there are longer power supply cable runs keep them away (>100mm) from all other cables. If you have to cross other cables do this at right angles.
3. Power cable location.
Keep the 240VAC Power cable away from all of your other cables and devices.
Keep the DC power cables to a minimum length (no coils) but long enough so you can rout them clear of other LED light extension cables and very definitely away from your DMX or E1.31 ethernet cables. Nothing closer than 100mm to your DMX cables or you are asking for noise issues (and blinky lights when you don't want them to blink).
Better to install stick on or screw on cable tie bases and cable ties to hold the wires in position. (you should also do this for your extension cables to LED strings and RGB lights so that when the cables get pulled they do not pull out the wires from your output terminals or bend the boards).
4. DMX/Ethernet network Cable.
Keeping noise out of your network cable is the core issue.
- Do not coil network cables as this will increase the chance to pick up noise.
- Keep cables as short as practical, but not so tight that there is strain on connectors or so that you pull the cable across other devices and cables.
- Keep network cable at least 100mm from devices such as power supplies and output modules. Only time this is not possible is where they connect to your output modules.
- If the connection to DMX on your board is via terminals rather than RJ45 connector then you are probably only using the orange/orange-white wires. Don't just leave the other wires floating around. Join them to earth AT ONE END.
Another issue is the DMX signal bouncing around. This happens when you don't have the opposite end of the DMX network to your DMX driver (e.g. ENTTEC Pro or similar) terminated. Many dimmer boards have links to set for terminating resistor. You only need ONE on the last module on your network on the DMX out cable from the last module. Better to make a short extension cable (say 300 mm) and solder a 120 OHM resistor between the two wires on the outer end.
Take care with these points and you will avoid most noise issues.
Good luck this year
