Denali v2 issue with Lexicon amp

[RLF]

In my home the theater system, I use both a Shunyata Triton v3 and Denali v2 to power all my gear. The Denali runs off of one dedicated AC line while the Triton runs off a 2nd dedicated AC line. I have a Lexicon class D amp for my Atmos ceiling channels which I have been using with my Triton for quite a while. The Denali has been recently added to my system.

Today I was experimenting with trying different components into different outlets of my Shunyata conditioners. Normally I run the Lexicon off of the Triton. When I decided to try the Lexicon plugged into the Denali today, I got a rather loud buzzing sound emanating from my Atmos ceiling speakers. I tried plugging the Lexicon into different outlets of the Denali, turned off my sub, swapped components around into different outlets of the Triton and Denali, tried a different power cord to The Lexicon, but no matter what I did, every time I plugged the Lexicon into the Denali the buzz returned. However, there is absolutely no buzzing when the Lexicon is powered by the Triton. All gear is grounded. The buzz is similar to the sound that some old CRT TVs make, but it’s coming from the speakers; not the Denali or Lexicon.

Although it is a simple matter of keeping the Lexicon plugged into the Triton rather than the Denali to solve the buzzing, it is very puzzling why it cannot be plugged into the Denali.

Any ideas?

[Masterlu]

Did you try swapping power conditioners with your dedicated outlets?

One dedicated outlet may be on another phase A vs B.

[RLF]

Originally Posted by Masterlu

Did you try swapping power conditioners with your dedicated outlets?

One dedicated outlet may be on another phase A vs B.

Yes indeed, I’ll check on that too, but I highly doubt that it is the problem. Thanks for asking though and I appreciate your suggestion.

To give a bit of background, we had our entire electrical system upgraded by a top certified electrician per code and inspected by our city inspectors where we live as dictated by our strict city codes. We are located in a very high fire danger area in a dense wooded area which is just south of the recent deadly Northern California fires which occurred the past couple of years including the fire which destroyed the entire city of Paradise California just to the north of us. I’m sure that anyone who has read my reply has also read about those devastating fires with loss of life and property.

All my dedicated AC lines have been gone over by a fine tooth comb Including our new circuit breakers. It’s not something to be taken lightly in our area. We have had friends who have been adversely affected by the fires and know a family who lost their home to one of the recent fires near here.

I have sent a PM to Shunyata about my issue, but haven’t heard back from them yet. I bought both my Denali v2s new by a certified dealer. Both Denali’s behave perfectly except with that particular amp and there is no noise when plugged directly into either dedicated AC line in our A/V Room or into the Shunyata Triton.

Perhaps it is an anomaly between the Denali v2 and that particular amp or some other unknown cause? No matter what though, the cause needs to be determined.

[GrantS]

Hi Bob,

This looks like a grounding issue between the two dedicated lines. Likely there is a ground potential difference between the two lines and there may be sensitivity to that on the part of the Lexicon, or adding the Lexicon to the line brings out the issue.

When dedicated lines are installed for an audio/sound system, if there is any difference in the length between either line, that alone can cause a ground loop hum/buzz. Any difference such as different outlets, different gauge, different breaker ratings can cause an issue but it's usually that the length of one line is shorter than the other line. This is a common problem if the lines are not installed specifically to avoid that issue and the vast majority of electricians don't take that into account when installing dedicated lines. They simply run the length of wire required to get to the panel from each outlet.

The hum is not an issue with the Denali because it's a passive device and would not pose such an interactive issue, and never has.

You may want to try running a ground wire between one of the posts on the Denali and the Triton to unify the ground. If that doesn't work, feel free to call me and we can go down the list and trouble shoot. It's difficult to do this on a forum because I can't ask questions and break down the system in real time and things can be left out. Grounding issues can complicated and require needle/haystack work sometimes. It's not whether your components are grounded, it's whether they are all grounded at equal distances from the panel on the two separate lines.

I hope this helps, Bob, but if not feel free to call me. Today, I am moving my 4 college kids from one apartment to another for the new school year (Annual Fall ritual), but if you leave a VM I will get back to you as soon as time allows.

Best regards,

Grant

[W9TR]

Originally Posted by Masterlu

Did you try swapping power conditioners with your dedicated outlets?

One dedicated outlet may be on another phase A vs B.

Yes - make sure both your dedicated lines are on the same phase. This is something an electrician may not pay attention to during the installation unless you specify it explicitly. City codes and the NEC don’t address it.

You can check this with a voltmeter. Measure the voltage from hot to hot between the outlets for each dedicated line. It should be zero. If it is around 230 Vac, then you are on two different phases.

Tom

[RLF]

Originally Posted by GrantS

Hi Bob,

This looks like a grounding issue between the two dedicated lines. Likely there is a ground potential difference between the two lines and there may be sensitivity to that on the part of the Lexicon, or adding the Lexicon to the line brings out the issue.

When dedicated lines are installed for an audio/sound system, if there is any difference in the length between either line, that alone can cause a ground loop hum/buzz. Any difference such as different outlets, different gauge, different breaker ratings can cause an issue but it's usually that the length of one line is shorter than the other line. This is a common problem if the lines are not installed specifically to avoid that issue and the vast majority of electricians don't take that into account when installing dedicated lines. They simply run the length of wire required to get to the panel from each outlet.

The hum is not an issue with the Denali because it's a passive device and would not pose such an interactive issue, and never has.

You may want to try running a ground wire between one of the posts on the Denali and the Triton to unify the ground. If that doesn't work, feel free to call me and we can go down the list and trouble shoot. It's difficult to do this on a forum because I can't ask questions and break down the system in real time and things can be left out. Grounding issues can complicated and require needle/haystack work sometimes. It's not whether your components are grounded, it's whether they are all grounded at equal distances from the panel on the two separate lines.

I hope this helps, Bob, but if not feel free to call me. Today, I am moving my 4 college kids from one apartment to another for the new school year (Annual Fall ritual), but if you leave a VM I will get back to you as soon as time allows.

Best regards,

Grant

Hi Grant, Thanks for the most helpful reply and the offer to help. In the meantime, I’ll take your advice and try putting a ground wire between the Triton and Denali. Then for experimentation purposes, I’ll then move the Lexicon back to the Denali to see if that cures the buzz in that configuration. It that does mitigate the buzz then that will be a good measure if and when I change gear down the line. BTW, once that I plugged everything back to where it was originally, not only did the buzz disappear again, but everything actually yielded a better picture and sound. Go figure

Best wishes in getting your college kids moved to their new place which of course is top priority. It’s to believe that it’s already that time of year again.

Originally Posted by W9TR

Yes - make sure both your dedicated lines are on the same phase. This is something an electrician may not pay attention to during the installation unless you specify it explicitly. City codes and the NEC don’t address it.

You can check this with a voltmeter. Measure the voltage from hot to hot between the outlets for each dedicated line. It should be zero. If it is around 230 Vac, then you are on two different phases.

Tom

Hi Tom. Thanks for the most helpful reply. At some point I will try doing that or have my technician do it when he installs our new OLED, but in the meantime I’ll try both Ivan’s and Grant’s suggestions.

[Masterlu]

I have experienced this behavior before with "out of phase" dedicated outlets.

[RLF]

I decided to do some troubleshooting on my own before calling Grant. First I plugging the Lexicon amp directly into the same dedicated AC line which the Denali was plugged into, but not through the Denali itself. The buzz disappeared so this indicated that somehow the buzz was related to the Denali since it is on the same dedicated line and duplex that the Denali was plugged into. Then I took Grant’s advice and ran a ground wire between the ground post on the Denali and the one of the ground posts on Triton to unify the ground. This worked

[Puma Cat]

Originally Posted by RLF

I decided to do some troubleshooting on my own before calling Grant. First I plugging the Lexicon amp directly into the same dedicated AC line which the Denali was plugged into, but not through the Denali itself. The buzz disappeared so this indicated that somehow the buzz was related to the Denali since it is on the same dedicated line and duplex that the Denali was plugged into. Then I took Grant’s advice and ran a ground wire between the ground post on the Denali and the one of the ground posts on Triton to unify the ground. This worked

Sounds like you had a ground loop, then, maybe?

And running ground strap from Triton to Denali allowed the loop to be "grounded?"

[GrantS]

Hi Bob,

I'm happy this was solved. There are times that it's like unwinding a fishing reel to get at the knot.

I should have mentioned electrical phase. That is yet another variable that should be considered and matched. Another factor you may have run into is that the Triton and Denali internal grounding are handled differently from one another, so that could be contributing in your case.

The take away is that if anyone wants to get the benefit of dedicated lines, whether to separate amps, digital or other parts of the system, the two lines need to be twins from breaker to outlet-- same phase, same current rating, same exact length and gauge of wire and same outlets. Even with that, if the two power distributors have different ground plane architecture you could get hum.

This may be a good example of why the grounding posts come in handy. Thanks for running the experiment, Bob. Very glad that did the trick!

Best regards,
Grant