adamantiumxt Posted May 26, 2017 Author Share Posted May 26, 2017 Thanks for the advice PeterI just ran some tests using a better quality 12v supply (from a BT router). It worked, and the whirring sounds of the cheap 24v one were gone. However, there was still some buzzing, which remained when the volume was fully turned down. Is this something normal with these systems, is it still because of the power supply , or is it because of bad termination? Link to comment Share on other sites More sharing options...
alistermorton Posted May 26, 2017 Share Posted May 26, 2017 One way to eliminate PSU as a source of buzzing would be to substitute a battery. Link to comment Share on other sites More sharing options...
boatman Posted May 29, 2017 Share Posted May 29, 2017 Thanks for the advice PeterI just ran some tests using a better quality 12v supply (from a BT router). It worked, and the whirring sounds of the cheap 24v one were gone. However, there was still some buzzing, which remained when the volume was fully turned down. Is this something normal with these systems, is it still because of the power supply , or is it because of bad termination? Buzzing on Tecpro compatible comms systems usually comes from having both the PSU negative rail and the cable screen connected to mains earth and/or the XLR shells at some point in the system thus creating an earth loop. Ideally the PSU negative rail shouldn't be connected to mains earth at all and the cable screens (including any connector panels) should all be isolated from mains earth. Link to comment Share on other sites More sharing options...
pmiller056 Posted May 30, 2017 Share Posted May 30, 2017 Boatman - Fair comment. The system I was making up was using its own dedicated cabling that had no other connection to the screen. It probably would be prudent to add a 'ground lift' switch to the power supply if the system is used in a number of different places. Note that if the earth connection was removed from the output, the power supply must be a class 2 or double insulated one (most wall-wart power supplies are) to eliminate any potential risk of electric shock from the power supply. As suggested a battery supply is feasible - If you have hum and buzz problems on a battery supply, then you will have to start fault-finding elsewhere. Link to comment Share on other sites More sharing options...
alistermorton Posted May 30, 2017 Share Posted May 30, 2017 If you have hum and buzz problems on a battery supply, then you will have to start fault-finding elsewhere. Yup, which was why I suggested it. Once you have a nice silent system with a battery, you can go back to a mains supply and see if the noises reappear. Link to comment Share on other sites More sharing options...
adamantiumxt Posted May 30, 2017 Author Share Posted May 30, 2017 Ok, I managed to get it running temporarily hooked up to some batteries by holding some wires in place, and everything worked fine with no buzzing http://www.blue-room.org.uk/public/style_emoticons/default/rolleyes.gifMy current 'wall-wart' has no earthing pin, so I'm not sure if I should break it open and add in grounding as Peter suggested, or would that cause the issues that Boatman mentioned; or should I attempt to filter the output with more capacitors; or just ditch this supply altogether for a better one? Link to comment Share on other sites More sharing options...
timsabre Posted May 30, 2017 Share Posted May 30, 2017 Is your wall wart an older transformer type (bigger cubic lump rather than the switchmode long rectangular lump)? If so you are probably hearing ripple on the output, more capacitors may fix it, or just get a switchmode module which will be a lot more stable. Link to comment Share on other sites More sharing options...
adamantiumxt Posted May 31, 2017 Author Share Posted May 31, 2017 I think it's switch mode (longer rectangular, also pretty light) Link to comment Share on other sites More sharing options...
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