USB or MIDI to my DAW/Computer/iPad - signal loss, noise, problems, not recognized.
Using your instrument as a MIDI controller for a DAW is a common scenario. Since the introduction of USB and USB MIDI, this is usually the favourite way. But I'm sure that many of you already encounter the problem of the so-called "ground loop noise" when audio is connected and also USB (or a MIDI cable) is connected to a specific rig. In the market there are also a lot of devices called "USB isolator" that separate the two parts of the rig trying to eliminate the problem. For example this is an interesting article: https://ifi-audio.com/wp-content/uploads/2019/01/iFi-audio-USB-Audio-Gremlins-Exposed.-.pdf
Our approach to this problem is a little bit different and, in a few cases (everyone is very specific, so we can't replicate EVERY case in the world and we can't physically go in every customer's house to check in person) our "loop eliminator internal circuit design" can create MIDI data transfer issues, especially with laptops, tablets and portable computers, devices usually in Class II. Sometimes the USB device is not recognized too.
It is not important here to technically explain how it works but let say that the audio circuit ground of our instruments is more powerful than the digital circuit ground, in this way experiencing that noise is very rare. This also has do to with the fact that our instruments are also usually in Class II (so without the earth connection) and many laptops are the same... the combination of the two is creating a floating system. So, when you connect only the USB (or MIDI) cable to your computer system, the ground of it in conjunction with the ground of your computer (most of the times floating from earth) is very poor and, as result, you will lose the connection and/or have faulty MIDI messages or other strange behaviours.
In such a case there's a solution: you have to connect your system to a trusty ground source (for example a MIXER or an AMP): but how to achieve this? The best way is to connect 2 audio lines from your keyboard to the same mixer where your DAW is connected even if you are not using the audio lines of your keyboard. You can also use the headphones out. Another way can be to connect your keyboard audio lines directly to the audio IN lines of your audiocard (if you have one) or to your computer. Please also check your ground/earth connections: sometimes using a cable without earth where is required is the source of the problem... I know, maybe you removed it because, in this way, you finally solved and annoying problem of ground loop but... it was required! You really didn't solve the problem, you just found an easy shortcut to solve a problem but then you created another one.
Sometimes is only a matter of trying.
Please also keep in mind that saying "I don't have this specific problem with all my other keyboards" is not making a lot of sense here: we, manufacturers, don't use the exact same circuits and components and we have different approaches.