Just installed my new Node Icon - getting hum through XLR connectors; some sort of ground loop problem?
Beantwortet
I just installed a brand new Node Icon, replacing an old Logitech Transporter and Krell KRC-3 pre-amp (which I'd also like to stop using), making the Icon the "volume knob". I'm using the XLR connections to go directly into an Apogee Mini-Grand DAX (one of the reasons I went with the Icon - for the XLR), and from there to a pair of Krell amps, which in turn drive my speakers (Apogee Mini-Grand). Cables came over from a previous system, and are known to be good (no hum there); also swapped them out for completely different sets, no problem.
I'm getting a hum through the Stages when wired directly to the DAX. When I put the Krell KRC-3 pre-amp back into the audio path, the hum goes away. Is this ground loop problem? Could this be a bum Icon?
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Offizieller Kommentar
Hi, I am just another user but if the ICON is working directly with the Krell Pre (and to the Kell amps) with the Apogee removed it would either point to an incompatibility / fault with the Apogee or as you say a ground loop introduced rather than a “bum” ICON.
Best to contact Bluesound Support via the BluOS App for further assistance.
You could try a an odd piece of wire and ground the Apogee, personally I would probably be looking to drop the Apogee and the Krell pre (which you are already planning to do) and then any audio room tweaking / filtering would be done using DIRAC on the ICON when it gets released making for a much simpler system.
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Thanks Seppi, but I think I may have not been clear about my setup. Original setup was Logitech Transporter to Krell preamp to Apogee DAX to two sets of Krell amps and then finally to the Apogee speakers. I tried to take both the Transporter and the Krell pre-amp out of the picture, connecting the ICON to the Apogee Dax, which is where I heard the hum. I had to re-insert the Krell preamp to remove the hum. I can't remove the Apogee Dax without replacing it with some other crossover component.
I'll reach out to Bluesound Support, to see if they have any suggestion.
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Same exact issue here. Sounds like they didn’t design the XLR output stage correctly or even bother with it at all. It can’t be in standby state or muted or else it will constantly buzz.
RCA works but why even bother having XLR if it’s not designed correctly to be used?
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Darn. I hope I don’t run into this issue with my Node Icon on order. This is a ground loop. I wish audiophile manufacturers would take the time to simplify grounding with a lug.
You need (Bluesound needs…) to find a way to get the ground of the Node to tie to the ground of your amps. Something like the outer shell of the RCA to the same ground of the surge protector of your amps should work. (That’s why some power centers like the Panamax line have a ground lug).
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After back and forth with support, they suggested I return the device since it's still in 30 day period and it's a hardware issue.
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I was wondering about this; since the power is just 2-prong without a ground; how would they ground the XLR connections. I'm disappointed to hear this as I was planning on connecting a 2nd device using the XLR/balanced connection - but if it's not grounded - seems to defeat the purpose of it.
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Interesting, so even in their support article, they stating that the XLR connection doesn't work properly and recommend using RCA. Sort of makes the XLR connection unusable and makes me wonder, like others, why they bothered if they weren't going to do it properly.
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Not an expert here, but from the article I understand that the simple fact of connecting a RCA cable should level out the ground between devices using the ground connection of the cable itself.
This in my opinion does not mean you need to actually use the analog out over RCA.
I think this is the principle of floating ground used by Bluesound. But maybe someone from Bluesound can enlighten us
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As stated in the KB Article Seppi referenced, Bluesound NODEs (all models) use a preferred style of a floating ground.
This is by design as in most preamps, generally speaking, you should only have one ground in your system to avoid an earth loop. Most often this happens with the amplifier. Ground loops can be caused by other issues though such as the NODE (any model) being plugged into a different circuit than the Amp.
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I recently connected the Node Icon to my new monoblock amplifiers, which only have XLR inputs. Upon connection, I encountered a persistent buzzing noise emanating from the speakers.
Crucially, this noise persists even after powering off the Node Icon (Removeing the power cord from NODE ICON). The only way to eliminate the noise is to disconnect the XLR cables from both amplifiers.
This issue is extremely frustrating, especially considering that I recently purchased a Dirac Live license specifically for the Node Icon.
I am concerned that this persistent noise renders the XLR outputs unusable with my current system and may necessitate the return of the Node Icon.
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Exactly the problem. There’s unfortunately no fix for it. It was a design decision to make the product have XLRs but not design it to work properly. Support and tech support said “audiophiles prefer using a floating ground”. I haven’t seen a single audio device not run of a standard AC power cable. Hell, the only devices that I know that still are designed with that are my PlayStation and Xbox.
I’d prefer to not have a poorly implemented XLR connection instead. I think that’s what audiophiles want.
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It’s definitely frustrating. Worse for me since I am still in queue for my Node Icon and have no idea whether or not it’s going to work in my setup without a human. For what it’s worth, Arcam, Marantz and Yamaha flagship gear uses two prong AC with XLR. There are definitely premium products out there that use a floating ground.
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I was thinking of competition like Eversolo, and Cambridge audio but it seems like their lower tier devices do use two prong but their network streamers use standard AC.
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Marantz Link 10n is $12,000 and uses two prong AC. So two and three prong is more like driver or passenger side fuel tank for cars.
The real problem is that we don’t know a priori if our audio setup will have hum or not. For people with in home trials or return windows with no restocking fee, it’s more hassle than deal breaker. But man, if there are workarounds as described, Bluesound Support needs to offer free cables to owners…
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Hi Alan et al
Your Authorised Bluesound Dealer or Reseller has tremendous experience in dealing with ground loop issues as they are not uncommon in home audio systems. You can also contact support@bluesound.com if the above recommended Help Centre Article cannot work for you.
Just a reminder that if your run is less than 2m (~6"), there is no advantage to using balanced connectors over RCA connectors. XLR cables only become advantageous to prevent attention over longer runs.
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A fix for this if your amp only has XLR inputs, just use and RCA to XLR cable. Amazon has them. If the run is short 4-6 feet, you wont notice a difference. There is tons of research out there to support the theory XLR is for really long runs. Another thing we could measure for specifically, does the RCA on the ICON provide less voltage than the XLR, because then you might notice a difference in SPL output, but no difference in sound quality.
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