Leaderboard

Just an update. I went to a local store and bought myself a Roland UM-One mk2 . The cable cost me 39 euro and when connecting it like described above i get no noise. A very good midi clock to the midiphy from Ableton and Bitwig . Updating with Mios Studio works. Bad thing is that it requires drivers but hey for now a driver is better then noise :) Probably and midi interface would have done what i now describe but just for the info :) Cheers Guys, i am happy again. Goodbye to ground noise and hello to white noise :)

Hi Niels, The power situation is fairly complex and there could be more than one source of noise. Some setups have no issues, some do. With MIDI obviously we have optoisolation so things are different there. The power distribution in the SEQ could be better e.g. by improving the return current path (certain Molex connectors on the lemec boards/USB PCB are meant for this). I think that the LED matrices introduce some digital noise as they switch. I'm not sure if this the source of your noise or whether it is the more commonly observed phenomenon encountered when connecting USB audio devices. Could be that your USB +5V from the computer is not designed for the current that you draw from it or is inherently noisy. Peter tested a laptop and USB power bank, which were both quieter than even a phone charger, but a PC tower had a much noisier +5V line. He could filter out some of that noise but it was still worse than the laptop. His Eurorack PSU is transformer based with linear regulators and uses a copper bussboard. I would consider this system superior to a switching PSU and a flying busboard. I would tend towards the powered USB hub like TK. uses for the SEQ. Another user still had issues with their hub but then one might imagine that that PSU was also noisy. Very hard to guess. There are also solutions to galvanically isolate USB and could be worth a try? Some are quite cheap and some much more expensive. I can't guarantee anything though, so it might be throwing money at the problem without a satisfactory result. For the Euroceiver ground lift, the RS-485 standard recommends to keep the 0V reference connected, even though the power supplies on either end could be mutually floating. Imagine an extreme case where you have a long signal cable and a device either end. You have a massive antenna and a real "ground loop" if the power supplies are connected. In our case, we can have two different power supplies and we keep the signalling within the common-mode range by referencing to a common potential (0V). Without J0 jumpered, the signals may become more susceptible to data corruption as the differential voltages drift apart. You might notice that the setup works in your studio but not at a gig for example. Instead of leaving J0 unjumpered you could try to connect a low-value resistor (say 10R) of suitable power rating across it. This might attenuate the noise that you hear. Best regards, Andy