Rose RS451 audible hum

ROSE Products RS451
#21

Hello @burki ,

I would like to ask about the hum noise issue related to the RS451.

Based on the posts you shared, it appears that the hum noise is coming from the RS451 unit itself rather than from the speakers. As you are very familiar with audio equipment, you will know that hum noise can be caused by various factors. It may be due to a fault in the SMPS or transformer inside the product, but it can also be caused by environmental factors including ground loop.

If the internal SMPS or transformer is defective, replacing the component would be necessary to resolve the issue. However, sending the product back to the dealer can be quite inconvenient.

For this reason, I would recommend checking the surrounding environment and grounding first before sending the unit to the dealer as a last resort.

Would it be possible to connect the RS451 directly to a wall outlet rather than through a power strip?
If there is a dedicated outlet with no other audio or network devices nearby, that would be even better.

Best Regards,

#22

If you go to YouTube thereā€™s an audio reviewer in California who is reviewing a set of Orchard Audio mono blocks.

He complained of a slightly audible hum when there is nothing playingā€¦ and his ear is next to the speaker.

Leo the founder of OA told him to get a device to help filter the power. (You can watch the video to see what its about. You can search for Orchard Audio review to see this. I think the reviewer is Ruiz.)

The point here is that if the issue is w the incoming powerā€¦ going over to a friendā€™s house may not solve it. Most likely its going to have the same issues unless your friend lives on the other side of town and its a large town / small city.

Iā€™ve been luckyā€¦ for meā€¦ I lived 20yrs a block away from the local sub station.
Now Iā€™m less than 1/4 mile from the local one, and in new construction.

So Iā€™d say it could be the power, not the unit. Something to check out.

#23

I have a test unit at home and Iā€™ve noticed a background noise when a song starts at a very low volume (a kind of pinkish sound). If I pause it at that moment, the noise stops.
Iā€™ve also noticed it when using streaming platforms.

Perhaps doing tests so close to the speakers isnā€™t helpful?

Iā€™ve also found that the equalizer isnā€™t working properly (it works even worse if you use the app).
My unit does not have the transformer hum.

And I almost forgot, the VU meters freeze after a few minutes

Iā€™ll turn it on again today to see if it works better.

Update: I played the same song on a CD player using a coaxial input and I donā€™t detect the pink sound.
Update 2: Detected the same sound (as if played from a tape) with songs from the hard drive (perhaps a little less)
Update 3: When playing video files, (from HD) the ā€œpinkā€ sound is not detected.
Update 4: It appears that the VU meters start working again by pressing the ā€œreloadā€ button.

#24

Try with an external battery like Bluetti or ecoflow ā€¦ so you ca isolated the problem

#25

A test unit? Okā€¦

So what does your set up look like?
Where do you live? Quality of power ?

Then what does your setup look like?
What does your internet connection look like?

#26

Hi !
My setup is a preamp and power amp, using the RS451 as the preamp.

I live in Spainā€¦ and my power quality isnā€™t the best, but itā€™s not the worst either. I use a filtered power strip with decent Isotek cablesā€¦ sometimes I use a Bluetti battery to power the equipmentā€¦ I detect pink noise equally well with the battery or direct AC power.

My connection Itā€™s very fast (fiber optic(, and the equipment is connected via Ethernet cable.

#27

Filtered power strip? Sounds like surge protection only.
And you hear this even if there is nothing plugged in to the unit but the power cable?

Iā€™d say send it back and exchange it. Something isnā€™t right.