Hum through speakers when Mini is on

[Geoff Hammond]

Hi All

I have a Wiim Mini with the Aux Out connected by cables to the Tuner input on a preamp. This system has recently developed a hum when the Mini is turned on (it's a 50-Hz hum, I'm in Australia). The hum is noticeable with the power amp volume control turned down completely, and increases as the volume control is increased. I've tried relocating the Mini and routing the Aux Out to the CD/Aux input on the preamp without any success. Thank you for your suggestions of a fix for this problem.

Geoff Hammond

 

[Mr Ee]

Hi All

I have a Wiim Mini with the Aux Out connected by cables to the Tuner input on a preamp. This system has recently developed a hum when the Mini is turned on (it's a 50-Hz hum, I'm in Australia). The hum is noticeable with the power amp volume control turned down completely, and increases as the volume control is increased. I've tried relocating the Mini and routing the Aux Out to the CD/Aux input on the preamp without any success. Thank you for your suggestions of a fix for this problem.

Geoff Hammond

If you remove the cable at the mini end does it still hum?
How is the mini powered? Supplied plug in a 'normal' plug socket? USB outlet on a powerboard?

 

[Doublej]

If you have them, you can trying a different RCA cable, and a different power supply/power supply cable. If you jiggle the WiiM, the cables or the power supply brick does the noise change in volume?

 

[Geoff Hammond]

If you remove the cable at the mini end does it still hum?
How is the mini powered? Supplied plug in a 'normal' plug socket? USB outlet on a powerboard?

The hum stops when I remove the signal cable from the Wiim. It’s powered
by the supplied plug into a normal power output.

 

[Geoff Hammond]

If you have them, you can trying a different RCA cable, and a different power supply/power supply cable. If you jiggle the WiiM, the cables or the power supply brick does the noise change in volume?

 

[merifon]

Maybe this could help, if I power my iPhone doing guitar modeling, connected to a powered speaker, if I use an Huawei power supply, I get some hum noise, especially when string are not touched. If I use the original iPhone power supply, no hum at all...
You could try another power or change the power wall inlet or better, manage to go with toslink...

 

[Geoff Hammond]

I’ll try another RAC cable and post what happens. I haven’t noticed any change in the hum when I move or juggle the Mini or the cables but I’ll look more systematically.

Thanks guys for your replies.

 

[Geoff Hammond]

Maybe this could help, if I power my iPhone doing guitar modeling, connected to a powered speaker, if I use an Huawei power supply, I get some hum noise, especially when string are not touched. If I use the original iPhone power supply, no hum at all...
You could try another power or change the power wall inlet or better, manage to go with toslink...

Thanks—I’ll try another power outlet.

 

[Geoff Hammond]

Thanks everyone. The hum problem seems to have resolved after (1) using a different power outlet for the Mini; (2) replacing the signal cable from the Mini to the preamp; and (3) separating signal and power cables as much as possible.

Don't know if any one of these was effective or a combination did it.

 

[bherren]

Could have been a ground loop...

 

[BowsAndArrows]

Yes, it sounds like a ground loop issue you had. I think changing outlets did the trick for you in this case. The best way of knowing for sure is to run off battery power vs the outlet you were using. If the hum comes back when plugged in then it was the outlet

 

[Geoff Hammond]

Finally, a resolution: the source of the hum was the power supply to the Wiim Mini (240V --> %v, 1A). Replaced the power supply with an iPhone charger and there was no hum.

 

[kalle]

hooked up to active speakers i get hum from the mini in standby mode, when i connect to spotify it goes away (atleast most of it). i assumed it was normal given speakers at 0db and possibly somewhat higher gain. is it just me?
using an apple 1A slim charger

 

[cooky560]

No that’s not normal. I have total silence from system when nothing is playing, regardless of the input. Grounding issues were common in analog setups. I hope you find the cause!

 

[kashsoni]

hooked up to active speakers i get hum from the mini in standby mode, when i connect to spotify it goes away (atleast most of it). i assumed it was normal given speakers at 0db and possibly somewhat higher gain. is it just me?
using an apple 1A slim charger

I found using the included power supply stopped by hissing.

I was using a third party power supply initially with 6 x usb-c outputs for all my amps and all had hissing.

 

[Steve Woodhouse]

Sounds like a ground loop.

The obvious way to fix it is to run optical out from the Mini into a cheap DAC; the SMSL SU-1 would be perfect.

For clarity, optical connections help stop ground loops as there’s no direct electrical connection, as the signal is carried optically, not be electric current.

The added advantage is that you’ll get better sound quality from the SMSL than the Mini’s internal DAC.

 

[Jls]

Thanks everyone. The hum problem seems to have resolved after (1) using a different power outlet for the Mini; (2) replacing the signal cable from the Mini to the preamp; and (3) separating signal and power cables as much as possible.

Don't know if any one of these was effective or a combination did it.

One of the outlets in my house is miswired. I don’t know which one. It was reported by the inspector at the time of purchase, but failed to specify which of a hundred it is.

If using a different outlet helps, perhaps the outlet is miswired.