Cable Vendor Recommendation Please

I’m having 60hz speaker hum which I’ve tracked to my DAC. But before I do something expensive, its been suggested that I swap out cables. Problem is, I don’t have any spares which would qualify as a “good solution”.

Need a mid-range supplier for a short BNC and a 3ft RCA. To give you an idea of the equipment quality, they’re going in to and out of a Yggy, a DigiOne, and an MRX720 powering wired Paradigm speakers.

Many thanks in advance for your thoughts and recs. John

I don’t think a different brand of cable will solve your ground loop issue.

Different cable choice might. Can you switch to balanced out of the Yggdrasil?

Not necessarily true. I once had a bad ground hum with a particular brand of cable and when I switched it out the hum went away. It certainly can be the cable.

Jeff, I have balanced out of Yggy, but not into the 720. So it’s gotta stay RCA in the short run, although I can switch to the second set of RCA outputs.

BTW, I know nothing about speaker noise types, but I went to some Info-ad website, and my sound matched up with a track they call “mechanical hum”. “Ground loop” sounded more like a buzz. Could be true or not.

Just to fill things out:

  1. Sound becomes audible across the room at -28dB, up close at maybe -31dB
  2. Hum is limited to one channel, Analog 2 coming from Yggy.
  3. I changed the Roon path to use Oppo as endpoint, circumvent DigiOne and Yggy, into Analog 1. The sound ceased.
  4. Back with the troubled path, I tried unplugging and plugging devices (other than the MRX). Unplugged DigiOne. No change. Switch Yggy OFF. No change. Unplugged Yggy. Hum stopped.

So I infer that the problem is with 720, Yggy, or interaction of the two. Correct inference? [haven’t done this before]. Most likely Yggy since no hum on any of the other 7 sources going into the 720, and Yggy’s the most recent change.

If I missed a step, please enlighten. Thanks much.


Uggh… ground loops are a nightmare.

Do you have these components plugged into different outlets (i.e. the amps plugged in to an outlet a distance from the speakers)?

You misread. As per my (lame) source, its mechanical hum. But consider the source.

If you think it related to the Yggdrasil and seems to be only be one speaker, have you swapped the L & R cables to see if the noise moves with the cable?

The speakers are ceiling types (Paradigm) and are between 6-10 feet away. BUT

There is a boatload of warts and outlets in the nearby wall cabinet. There is only one dedicated electrical line leading to the breaker box. And…no LPSes to be found. [I might as well confess now.}

Jeff, or Dr.T, I stood under the three front ceiling speakers. Hum definitely out of L and R, seemed like no for M. But haven’t swapped.

To answer the initial question, I have had good luck with Blue Jeans Cable.


Sorry I misunderstood your previous post, I thought you meant one speaker but you meant one source. My bad.

What’s in front of the Yggdrasil?

Ropieee DigiOne connected by BNC

Ignore I really need to read the full post before replying.

This is most definitely a ground loop.

This doesn’t mean that there’s anything wrong, but it is going to be something that you’re going to have a hell of a time dealing with. New cables likely won’t solve it.

First off is there anything else connected to the Anthem? TV, Oppo, cable box?

With Analog 2 chosen on your Anthem and the hum being created, try physically disconnecting the other Anthem inputs and outputs excluding the speakers of course.

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Oh yes, Andrew and you are striking near the core of my fear.

Attached to the 720 is: a TiVo; Apple TV; Roku; Oppo; Yggy/Roon trail; and Sonos. (First three HDML, last two analog)

[ at this point, I pause to allow the giggling to subside].

This is in a 4 X 6 two-shelf cabinet with an HDTV above the cabinet. Also nearby are: a Control4 controller; a Nighthawk 3000 configured as a wireless access point; and a Netgear wireless switch.

And, all of the above is all eventually fed, through a series of surge protectors, to a single electrical line to the circuit breaker.

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Sorry, DT, but I am away from my unit til Monday. But I’m taking notes.

Try disconnecting the coax connection from the TiVo (or disconnect the HDMI). If the hum goes away then you have exactly the same problem I had a while back and I can point you at a solution.

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Ah… missed that so I’ll give you a little more info here.

CableTV is the source of this problem in many scenarios like this. The issue is that the cable line is grounded in multiple places including where it enters the home. They typically ground it to a water line or or the outside of the electrical panel, but never to the ground bus inside the panel. Because of this there is a significant difference in ground potential between the shield on the coax cable the the third prong of your electrical outlet. This causes a current to flow (at 60Hz frequency) between the cable ground (shield) and the closest thing that is connected to the ground bus in your electrical panel. The TiVo is ungrounded and the receiver is ungrounded so the next thing in line is the DAC. There’s actually a current flowing between the DAC’s ground and the cable’s ground and it’s riding on top of that single-ended interconnect! That’s where the hum is coming from. Unplugging the DAC from the wall eliminates that path and the current stops.

So… if you disconnect the cable from the TiVo (or the TiVo from the Anthem) and the hum stops then you need to break one side of that ground. I don’t suggest lifting the ground on the DAC as that’s a safety issue, but you can lift the ground on the cable line. Just pickup one of these:

If you have a coax line into your TV as well then you’ll need one there too.

Andrew, thanks for both the tip and explanation! Makes good sense and I will attend to that first thing.

As an editorial comment, this crowd of this and other threads has amplified my knowledge and way of thinking about problems, and I thank you all for all the present and future suggestions. John

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