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3.5mm jack to 2 x XLR

haen

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Hi.

I'm looking for a pair of desktop speakers and I was almost sold on Adam T5V when I noticed that their depth is almost 30cm, which is over 11cm more than my current speakers. I can still decide to buy them, but I also went back to the list of recommended active speakers and ROKIT 5 G4 could be another contender which less excessive depth (24cm). One gotcha here is that those speakers have only (balanced) TRS/XLR combo jacks. In the long term I may pick up some DAC + headphone amp, but for now I've planned to connect new speakers directly to the sound card. So for an ignorant person tha I am it looked like I need to buy a 3.5mm (or 1/8 inch) to 2 x XLR cable. Is there any gotcha with those? I've found following information in manuals on the KRK site:

Note: Your Rokit G4 monitors have friction lock, Neutrik combo connectors for the input. Use an
XLR cable or TRS (tip, ring, sleave) 1/4” balanced cables to connect to your interface, mixing board
or monitor controller. You can use an 1/8” to Stereo 1/4” unbalanced (mono) to hook up directly to
a phone, computer or music player. (CAUTION: Be sure the volume on your device is set to
minimum and then adjust to taste.)

If you are using an unbalanced output to balanced cable conversion, make sure it is correct. The shield is connected to the unbalanced ground of the source
and pins 1 and 3 of the XLR (or the sleeve and ring on the ¼” TRS jack).

Is e.g. this cable - https://www.amazon.com/Cable-Matters-3-5mm-Inch-Breakout/dp/B07PJXKKX6 - an appropriate one? Or https://www.amazon.pl/MOBOREST-podwójny-polączeniowy-stereo-mikrofonem/dp/B07V6QS5G9 (the description is in Polish but the pictures shows some data in English).
 

Berwhale

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Looks like the 3.5mm GND is connected to pins 1 & 3 as required, so it should be fine....

1632592344085.png
 

AnalogSteph

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Well, "fine" if you are willing to put up with some amount of ground loop noises. Cable #2 at least looks like you may be able to access the connections inside the XLR plugs and rework them. You'd want to replace the 1+3 connections by one to 3 only.

Plan B, acquire a Behringer HD400 plus cables 3.5 mm to 2x 6.35 mm TS and 2 pcs. 6.35 mm TRS to XLR male (the latter not too long); I suggest a store for music equipment rather than generic Amazon (pretty sure Thomann ships to Poland as well but there may be more local options).
 

Zek

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I think that colors for positive signal are reversed - tip on 3.5mm jack is Left channel and ring is Right channel.
35-mm-to-2-x-xlr.jpg
 

DVDdoug

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have only (balanced) TRS/XLR combo jacks.
With an unbalanced source you can usually use a TS plug that "shorts" the "extra" input-terminal to ground. So, a pair of adapters like this and a 3.5mm to stereo RCA adapter cable.
 

Berwhale

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Well, "fine" if you are willing to put up with some amount of ground loop noises. Cable #2 at least looks like you may be able to access the connections inside the XLR plugs and rework them. You'd want to replace the 1+3 connections by one to 3 only.

There's been a fair bit of discussion regarding the required connections on ASR, for example...


The consensus seems to be to connect both 1 & 3 to ground, but possibly at different ends of the cable. There are also reports that removing ground from pin 1 has solved ground loops. However, given that most, if not all, of the manufacturers suggest connecting both 1 & 3, I'm wondering what the downside of not connecting pin 1 to ground is? For example, can this cause a problem for the amplifier in the powered monitor?
 

AnalogSteph

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However, given that most, if not all, of the manufacturers suggest connecting both 1 & 3, I'm wondering what the downside of not connecting pin 1 to ground is?
The user has to make sure that there is in fact another ground connection already present. If the source is floating around near half the mains voltage, the input may be subjected to substantial amounts of common-mode voltage otherwise, taxing the limits of its CMRR and eventually even the supplies. This would result in a rather nasty hum at the very least.

So if all you have is a DAC powered by a little wall wart and connected via Toslink, chances are you want a cable that splits output ground and does connect shield at the other end.
 
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daftcombo

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I don't understand. I bought a random 3.5mm to 2xXLR cheap cable in a pro shop to connect Genelec 8020B to the output of a random soundcard, and it was fine.
 

Berwhale

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So if all you have is a DAC powered by a little wall wart and connected via Toslink, chances are you want a cable that splits output ground and does connect shield at the other end.

If you have a DAC that is...

1. Powered by a wall wart, which in my experience never have any connection to safety ground (ground pin on UK adapters is usually plastic)

and...

2. Opitcally isolated from any upstream components with Toslink.

How would there be any chance of a ground loop forming in the first place?
 
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haen

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Thx all for all the answers. For now I have bought some Cordial 3.5mm to 2 x XLR and I will see what happens.
Plan B, acquire a Behringer HD400 plus cables 3.5 mm to 2x 6.35 mm TS and 2 pcs. 6.35 mm TRS to XLR male (the latter not too long); I suggest a store for music equipment rather than generic Amazon (pretty sure Thomann ships to Poland as well but there may be more local options).
Thanks, I will probably try this combination if I hit some problems with ground loop, hums or noises.
Well, "fine" if you are willing to put up with some amount of ground loop noises. Cable #2 at least looks like you may be able to access the connections inside the XLR plugs and rework them. You'd want to replace the 1+3 connections by one to 3 only.
In general I would like you to avoid messing with cables myself, but what do you mean by 'You'd want to replace the 1+3 connections by one to 3 only.'?
The consensus seems to be to connect both 1 & 3 to ground, but possibly at different ends of the cable. There are also reports that removing ground from pin 1 has solved ground loops. However, given that most, if not all, of the manufacturers suggest connecting both 1 & 3, I'm wondering what the downside of not connecting pin 1 to ground is? For example, can this cause a problem for the amplifier in the powered monitor?
I remember reading several articles about ground loops and audio equipment and many of them strongly advised against cutting ground pines/wires due to safety reasons. Now, in general discussions like these unfortunately sort of fly over my head (they probably shouldn't, but...), so it may be something different you and AnalogSteps are talking about...
 
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haen

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For anyone interested - I connected KRK ROKIT 5 G4 to my PC using Cordial 3.5mm to 2 x XLR cable and so far I hear no hisses, hums or other unwanted noises. As Amir noted in his review those KRK produce in practice no hiss, unless one will place his ear really close to the speaker. It is a welcome change compared to my old M-Audio AV 40 which seem to get louder and louder as time passed. I understand that such things depends on configuration, devices and interconnections, so maybe I'm just lucky this time.
 
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haen

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Yes, the speakers and PC are plugged into the same outlet strip.

I've run Prime95 and GpuTest a bit, first without any sound being produced to see if it will trigger some noise/hiss, then with some FLAC in the loop mode. I could not spot any issues (actually half-expected some playback hiccups since all CPU cores got bogged down by Prime95 but no).
 
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