ID:Core Stereo 10 noise

[GeMir]

I've got my Blackstar ID:Core Stereo 10 (firmware version: 1.2.1) a week ago and it's quite noisy.

Here are my test results with clean sound in manual mode with gain set to 0:

• Volume 10, no instrument cable connected — no noise (amp mutes the speaker?)
• Volume 0, no instrument cable connected, USB cable connected — severe noise, annoying
• Volume 2, only instrument cable connected — slight noise
• Volume 5, only instrument cable connected — severe noise, annoying
• Volume 2, guitar volume 10/humbucker — slight noise
• Volume 5, guitar volume 10/humbucker — severe noise, annoying
• Volume 2, guitar volume 10/single-coil (middle) — slight noise
• Volume 5, guitar volume 10/single-coil (middle) — severe noise, annoying
• Volume 2, guitar volume 10/single-coil (neck) — slight noise
• Volume 5, guitar volume 10/single-coil (neck) — severe noise, annoying

"Slight noise" means it's a hearable constant noise and it doesn't sound line the "normal" 50/60 Hz hum.
Is it ok for this amp? Is there anything I can do against it (I've already did a factory reset)?

My guitar is a Squier Affinity Strat HSS and I'm using a Fender instrument cable.

[GeMir]

Today I was by a local guitar teacher with my rig and he said: this noise level is absolutely normal for any amp.
So, the "problem" is solved.