The faintest hum from Michi X3 through speakers

[Yetiuno]

I know this is well worn as a general topic...but here goes...

Any thoughts? Thanks! ...and happy new year!!

Hi,

I also bought a used Michi X3 S2 about a month ago and noticed a similar issue after just one week. In my case, it's a humming sound that affects both channels equally and, just like in your case, it's independent of the volume level.

What I have observed is that the humming becomes significantly less noticeable when the input selector is switching — for example, when I go from AUX to CD, while the relays are clicking, the hum decreases considerably, although it doesn’t disappear entirely.

As you mentioned, it’s not an unbearable issue, but you do expect more from a flagship amplifier from a brand like ROTEL. So now I’m wondering whether it’s a defect in my unit or something common across other units.

I’d be very interested to hear from other owners, and also to know how your case ended — did you return the amp or decide to keep it?

Best regards.

 

[Snoopy]

If you good hum and a DC Blocker or Ground Loop Filter doesn’t help I would return the amp.

 

[Yetiuno]

If you good hum and a DC Blocker or Ground Loop Filter doesn’t help I would return the amp.

But Isn't it expected that a device in this price range would already include such components in its power supply?

In any case, could you recommend an affordable power strip that includes them?

 

[Old_School_Brad]

Looks like the Michi amp has a ground (GND) terminal, which means it’s meant to be plugged into an outlet that actually has a proper ground connection. That might be important for this amplifier.

Before assuming there’s something wrong with the amp or chasing other issues, I’d make sure it’s plugged into a (proper) grounded outlet.

 

[Snoopy]

But Isn't it expected that a device in this price range would already include such components in its power supply?

In any case, could you recommend an affordable power strip that includes them?

I use a DC Blocker+ from the UK company IFI with my yamaha Amp.
The Yamaha has a floating ground , so I’m not concerned about Groundloops.

( Yamaha's 'Floating and Balanced' circuit topology i. This sees the circuitry within the unit electrically balanced throughout, while the 'floating' part means that it is not referenced to ground at any point. The result should be that any ground noise the amp encounters will have no effect on the signal that passes through it.)

I don’t know what rotel uses , but huge transformers will hum if DC offset gets to high.

 

[axiomofchoice]

@Yetiuno well, I guess I’m glad I’m not all alone with this issue. I kept it, mainly because I didn’t notice the problem before the seller’s “no questions asked” return window closed. I had the option to return it for inspection and repair, but I got the impression that this would qualify as “normal behavior” from their point of view.

I also checked if my outlets were properly grounded using a gadget I bought from Amazon. So that wasn’t the issue. Idk…seems like it might just be a problem with their design. I’ve learned to live with it, as I can’t actually hear it from normal listening positions. But yeah…it’s a disappointment…

 

[Yetiuno]

@axiomofchoice By the way, what’s your overall impression of the amplifier after a few months of use?

Personally, aside from the hum issue, I’m quite satisfied. My only complaint is the number of volume steps — I think it's a bit excessive. In practice, I find myself jumping five steps at a time, so in my opinion, 20 steps would be more than enough compared to the current 90. at any case, that should be adjustable via software, so hopefully it’s something they’ll address in a future update.

 

[axiomofchoice]

@Yetiuno sorry for the late reply. I’m otherwise generally satisfied. Besides the hum is an issue where my subwoofer pops at power on. This also should not happen for something in this price range. I was able to mitigate this by setting my subwoofer to auto power on, so that the pop happens before the subwoofer actually powers up.

Sonically, it works well in my system. I’m happy with that. Also the UI and remote are very artfully designed. But was it worth the money I paid? Idk.