MR816x - computer noise when recording inputs

Steinberg Hardware
1

I’m pulling my hair out for a few days now.
The MR816x’s are great, low noise floor, until I start up the computer, then all hell breaks loose.
Anytime I hook up an input to record there’s all kinds of noise from USB, power supply under load, moving objects on screen w/ mouse, high-pitched whines etc…It’s terrible, I can’t record anything. I’ve worked for a couple days with two completely separate computer systems and have same problem.

System 1
Hardware
Asus Sabertooth X58 Motherboard
Nvidia GeForce 9500GT dual-DVI w/ dual monitors
SIIG PCIe firewire (TI chipset)
Corsair TX650M power supply
6GB RAM, Intel Core i7 2.8GHZ CPU
(2) MR816x’s
(1) Midex8

Software
Cubase 5
Wavelab 5
MR816x drivers & tools

System 2
Hardware
Gigabyte X58 UD3R Motherboard
Nvidia GeForce 9500GT dual-DVI w/ dual monitors
SIIG PCIe firewire (TI chipset)
Corsair T650W power supply
6GB RAM, Intel Core i7 2.8GHZ CPU
(2) MR816x’s
(1) Midex8

Software
Cubase 5
Wavelab 5
MR816x drivers & tools

here is a sample fo the best case I was able to achieve (be careful I’ve recorded some synth bass notes as reference to noise so may be loud).

Basically there’s all kinds of noisy. Here’s some general notes.

  1. On System 1 the ($100/650w) power supply was terrible, and actually made noises on its own when under load. These same noises somehow worked their way into the audio. You can physical hear the power supply making these noises right next to you in the room, and then you can hear the same noises coming out the mains as it’s somehow coupled into the audio path.

  2. The noise here is not normal 60/120Hz line noise or ground loops, it’s other hash.

  3. When the CPU/power supply is under load the noise can go up and down in level or character. This happens on both systems.

  4. I tried to isolate the USB devices by rigging up a separate power supply for these devices (Steinberg Midex8 etc…). This did nothing since you still have to share the grounds of the two independent supplies.

  5. The noise got slightly better when using the PCIe Firewire interface versus the built in one but still bad.

  6. When I hook up a synth to the Midex8 via MIDI, and then setup to record the same synth into the MR816x, the noise gets much worse when the MIDI cable is plugged in. The Midex8 is connected to the computer via USB, so something is up with that.

  7. Concerning grounding I’ve tried everything. I’m in a dedicated studio…that I built myself. There’s separate circuits for computer, audio, lights, utility, eetc… I’ve tried many things, connecting all hardware to same circuit at exact same place, isolating certain pieces etc… every combination of grounding scheme you can think of. It’s really not that…its the frigin computer, it’s noisy as heck, and I think the switching power supplies are terrible.

I’m not a high end fanatic here, I just want to record sources without noise. I was going so crazy I wondered if anyone made a linear power supply for computers. I don’t think it’s possible because of current energy regulations (too inefficient), and size requirements, but I would die for it.

Any thoughts?

2

I had severe harddrive and computer noise on my monitors until I installed a ground loop isolator on my montior outputs. That was before the addition of the MR816x, but I also had very bad noise issues when I installed my MR816X and the power cord/brick would get too near the input/output cables in the back of the MR.