Speaker Hum from Gen 2 XPA-5 due to a wall wart

[dlaunde]

Weird issue. Just changed out a BASX-5150 for an XPA-5 Gen 2 and traced a very loud hum coming from all five speakers connected to the XPA-5 back to a single wall wart power a media client. This hum didn't happen with the BASX-5150 in the system and nothing else has changed. If just the XPA and media client are turned on the hum happens and goes away the moment I turn off the media client.

I tried a cheater plug on the XPA-5 but that didn't fix the issue. Best I can tell from reading around is this particular wall wart is "dirtying up" the AC circuit which is only affecting the XPA-5 possibly due to it (the XPA) having a Linear Power Supply. Not sure.

What's really weird is I have a few other wall warts in the setup powering other devices that aren't causing any hum issues.

Any suggestions? Should I try ordering a new wall wart (the one that came with this media client is very "cheap")?

Thanks

[KeithL]

It's possible.... but seems somewhat unlikely....

You mention that the hum goes away "when the media client is turned off".

My question would be about what the media client is connected to.

Specifically, is that media client connected to your preamp or pre/pro, which is then connected to the XPA-5?

If so, then the media client may be causing or contributing to some sort of ground loop.

It's also possible that the wall wart, or the wire going to it, is simply located near something sensitive, like an interconnect cable.

This is easy enough to test.

Disconnect the media client from the rest of your audio system.

Then turn it on and off while the rest of the system is running.

If the noise still occurs then you know the media client is causing it directly.

(So it may in fact be a bad wall wart or something similar - and replacing it would be a good first option.)

But, if the noise goes away when the media client isn't connected to the main system, then the cause is more likely some sort of ground loop.

(These can be trickier to solve.... and replacing the wall wart may still be the solution... but that's a lot less likely to be the case.)

(It's also worth noting that the XPA-5 Gen2 is more sensitive to ground loops and other ground issues than the 5150.)

Dec 18, 2019 17:15:10 GMT -5 dlaunde said:

Weird issue. Just changed out a BASX-5150 for an XPA-5 Gen 2 and traced a very loud hum coming from all five speakers connected to the XPA-5 back to a single wall wart power a media client. This hum didn't happen with the BASX-5150 in the system and nothing else has changed. If just the XPA and media client are turned on the hum happens and goes away the moment I turn off the media client.

I tried a cheater plug on the XPA-5 but that didn't fix the issue. Best I can tell from reading around is this particular wall wart is "dirtying up" the AC circuit which is only affecting the XPA-5 possibly due to it (the XPA) having a Linear Power Supply. Not sure.

What's really weird is I have a few other wall warts in the setup powering other devices that aren't causing any hum issues.

Any suggestions? Should I try ordering a new wall wart (the one that came with this media client is very "cheap")?

Thanks

[dlaunde]

Dec 18, 2019 17:50:44 GMT -5 KeithL said:

It's possible.... but seems somewhat unlikely....

You mention that the hum goes away "when the media client is turned off".

My question would be about what the media client is connected to.

Specifically, is that media client connected to your preamp or pre/pro, which is then connected to the XPA-5?

If so, then the media client may be causing or contributing to some sort of ground loop.

It's also possible that the wall wart, or the wire going to it, is simply located near something sensitive, like an interconnect cable.

This is easy enough to test.

Disconnect the media client from the rest of your audio system.

Then turn it on and off while the rest of the system is running.

If the noise still occurs then you know the media client is causing it directly.

(So it may in fact be a bad wall wart or something similar - and replacing it would be a good first option.)

But, if the noise goes away when the media client isn't connected to the main system, then the cause is more likely some sort of ground loop.

(These can be trickier to solve.... and replacing the wall wart may still be the solution... but that's a lot less likely to be the case.)

(It's also worth noting that the XPA-5 Gen2 is more sensitive to ground loops and other ground issues than the 5150.)

With just the media client powered on but not connected to anything else (no HDMI or Ethernet connection, just the power supply connected to my power strip) the hum still happens.

However....I somehow just fixed it. All I did was untangle the power cord to the wall wart as it had a small snag/loop right where it enters the plug adapter body and reseated it in the power strip.

Now all I hear out of my speakers is a very faint background hum that is present with just the amp on and nothing else which I'm assuming is the "floor noise" (is that the right word?). It can only be heard with my ear right up to the speaker. No issues with that, right?

[emofrmcgy]

Hey congrats on the addition of the funk 21... I'd like to see some pics.