Balanced Cable Discussion


#61

In my Tidal trial debacle, I can’t get the desktop app to play hifi/master quality. Instead, it only plays Normal. So far Tech Support has been useless, asking me questions I already gave them answers to in my initial question to them.

Android works fine though, so I decided to make an balanced 2.5mm to dual 3-pin XLR cable today to plug directly into my balanced amp(s). Seems to work just fine. :slight_smile:

I also made a second 2.5mm balance to Stereo RCA today to use at my second office location.


#62

The trailer doesn’t work if you only use headphones when you don’t want to blast the loudspeakers. Even assuming that you remove internal partitions from your trailer to create a room that has a length greater than 1/4 the wavelength of your bass tuning target. (Otherwise you will experience a 12 dB per octave roll off, and will therefore have to weld additional length into the frame of your trailer to compensate). Then there is the matter of reducing internal reflections from shorter wavelengths, Probably you ought to cut along the ceiling and side walls (non-linearly) and use a large English wheel to fit some pieces of sheet metal curved to minimize the reflections. After the divorce, you could consider buying a second trailer, and setting them on end, making each one into a fully satisfactorily sized transmission line.

No, I’m not sparing the random thoughts of a crazed old audiophile. Oooo, i’m Feeling attenuated.


#63

Problem with ground loop 120 hz hum. After changing tubes, single wiring dac and amp separately, I’m still pulling my hair out trying to fix it.
I recently moved my headphone setup into my living room where is bad. It was ever so faint in computer room I just came to live with it. I want to stay in my living room but do not want to live with the hum.

I have scoured the Google giant brain in the sky and watched several videos and articles on 120 hz hum. In the old days with my high $$$ 2 channel setup I use to simply let my pricey line conditioner. Easy peesy!

Now that I’m a poor old geezer on fixed income I’m not wanting to buy another conditioner. My Matrix Xsabre Pro dac is true fully balanced. My amp is my beloved Woo Audio SE 2nd gen. It is unbalanced.
I’ve been considering upgrading to the Woo Wa 22 SE 2nd gen which is balanced and would allow me to keep Sophia Princess rectifier, which I love. I’m talking about balanced, because all information is pointing me in the direction of balanced eliminates the problem.

My simple question despite my long diatribe is, from my learned friends here, fix this ground loop issue? I would prefer not buying hum eliminators and certainly not cutting off the safety ground for safety reasons. Any suggestions appreciated or confirmation of balanced amp purchased. @Torq


#64

Sorry. I should have added all my headphones are also balanced.


#65

Your headphones being balanced is immaterial here, so you can take that off the list of things too worry about.

The first thing to do is find out if it really is a ground loop. The most reliable quick way to do that is to grab a handful of ground-lift/cheater plugs (they’ll be about $1.50 at the hardware store), and add one to each piece of gear until the noise goes away. If that process fixes it, it’s a ground loop and then you can start looking at how best to address it for your particular setup without resorting to lifting one or more grounds permanently.

That it was present at a low level in one room, and is much more pronounced in another, makes me wonder if its not down to a cable TV box, and if that is the case (e.g. the above doesn’t fix it then it remains a possibility) you’ll need a cable TV isolation transformer.

Adding a balanced amp will not necessarily fix the issue.

Even in fully balanced systems you may need to add a DI box, or similar, (which is another type of isolating transformer, this time operating on the actual signal connections between gear), but those have their own issues since you’re adding transformers and additional cabling in the audio path.

Fancy power conditioners won’t always fix the issue either … nor will the “Hum X”.

So, first, do the ground-lift test and see if it really is down to a true ground loop and we can go from there.


#66

I’m in the process of tearing my whole set up apart and re-org, due to a hum in my tubes that wasn’t there a couple days ago…then realized it might be my new tubes :rofl: well I need to do some clean up and cable management anyways lol


#67

Change the tubes first. Any microphonics. External Hard drive nearby? Tube dampers are helpful as well.

Maybe some transformer vibration? Funny what causes these annoying hums.


#68

Yeah, it was irritating me as I finally had the BHC silent…

I took it to my garage work space and it still had the hum so I think it is just the new tubes breaking in, volume at zero and I get the vrrrm very slightly out of the headphones. I’m pretty positive that they are the issue. When I get home later today I’ll swap tubes and see if it makes a difference

Well after re-org, vrrmm… is gone, so…?


#69

I got the cheaters and plugged the amp and dac in separately using Audirvana on laptop with battery only. The hum became consideribly lower. I then plugged my Brickwall outlet into a cheater and then my amp into cheater into the Brickwall leaving Dac plugged into without cheater. All became nearly total black. Tiniest hum barely noticeable. How to sort out the loop eludes me for now. I certainly do not wante to continue the grounds lifted.


#70

To be of further help, I’d need to know what your “Brickwall outlet” is, as that sounds to me like the socket on the wall.


#71

I’m hoping these images will be enough info:


#72

I have a SMSL SU-8 incoming and I am planning to get XLR cables to run from it to my Kali LP-6 active monitors. I’ve been eyeing the Monoprice Monolith ones but I was wondering if there were any other mass market XLR cables with a braided nylon sheath that would be cheaper.


#73

Curious to hear how you like the SMSL. Considering pairing that with my THX 789 on the way.


#74

That helps.

So, try the following:

  • No cheaters on the DAC or AMP, but one on the Brickwall.
  • No cheater on the Brickwall, but one on each of the DAC and AMP.
  • No cheater on the Brickwall or the AMP but one on the DAC.
  • No cheater on the Brickwall or the DAC but one on the AMP.

If the quietest result is from the first test above, it’s likely to be noise on the ground line from elsewhere rather than a ground loop within the system itself.


#75

Massdrop has the XLR to 2.5mm TRRS adapter again: