I’m currently working on a new mobile setup with a lot of USB-powered gear, which eventually led to ground loop issues.
I’ve mostly found how to solve the issues, with separate USB power supply and some of these ground lift adapters from aliexpress: https://aliexpress.com/item/4000205467418.html
Still, I’m wondering if those cheap ground isolators affect the audio quality somehow. I’ve noticed that on some device with combined headphone/line output like the OP-Z, I get a severe loss of volume level. On other devices likes a Typhon or NTS-1, there’s no noticeable changes from a quick check. I suspect that these devices somehow alter the impedance, making some devices switch between the line and headphones mode, what do you think?
I heard that bigger isolators like the HD400 may have better quality, my problem is that it’s too big for my setup, as I need multiple isolators. I also tried an iDefender+ for USB isolation instead of audio isolation, it made the problem worse. As there’s USB midi involved with some devices with no other choice (like the OPZ), audio isolation is my only alternative.
FYI, in my setup there’s the two Digi, a Typhon, an OPZ, a NTS-1, a PO-35, a nanoKey studio, a Raspberry Pi and a Bluebox for mixing. OPZ and NTS-1 use USB-midi, others use “real” midi. NTS-1, Typhon and PO-35 needs audio isolation (too much volume loss on OP-Z). The PO-35 needs isolation as it received sync signal from NTS-1 (and audio isolation on sync signal breaks it as it dampens the volume).
My questions here:
- Do these cheap audio isolators affect audio quality? I really don’t want to ruin the good sound of synths like the Typhon…
- Is there higher quality alternatives for 3.5mm stereo jacks, in a compact format?
- How do you keep your sanity with complex setups involving USB-midi and ground loops?
Thanks for your wisdom.