Proper cable to join RCA to XLR balanced, help needed

[Paffi]

I tried the monoprice cable ("right one") and the cordial cable ("wrong" according here). Both have the same noise and hum in my setting, there was unfortunately no improvement.

 

[KSTR]

@Paffi, then further debugging is needed where your noise problem comes from...

 

[Neuropsychology]

I tried the monoprice cable ("right one") and the cordial cable ("wrong" according here). Both have the same noise and hum in my setting, there was unfortunately no improvement.

What is the right one do you have a link?

 

[Miguelón]

Answering to my own post, I found the solution to my problem with the 2 wired cable and tweaking the settings of the monitors.

I tried +6 dB (minimum gain) in the Genelec 8030C, tonality was altered. Even 0 dB sounded also altered but less, so I let by default setting (-6 dBu that’s it 106 dB @ 1V) and remembered WiiM Ultra has different voltage outputs. At -6 dB sensitivity I was using 18/100 of the volume, according to the specs of Genelec it reach the maximum at -2 dBu so 615 mV were needed: adjusting to 800 mV then sounded great!

It has also 500 mV and 200 mV but with 800 apparently I cover full range and let some headroom dBFS to EQ

106 dB @ 1Vrms is an insane amount of gain… WiiM claims no loose in accuracy at low volumes but IMO is not true, on the other side Genelec “prevents” in some way to reducing gain in their monitors but at the same time advice to using lowest sensitivity that produce distortion at 90% voltage of an audio interface (that’s +4 to +6 dB), but the attenuator color the sound.

At Thomann website many professionals use monitor controllers but the fews I found with “transparent” qualify by comments start from 500€. WiiM Ultra on 800mV is right to me, but Heritage Audio RAM 1000 apparently is a must have in the future…

Heritage Audio RAM 1000

Desktop Monitor Controller 24-Position rotary switch in 3 dB steps, Mono/Dim/Mute button, Bluetooth connectivity, LED meter for input level, Switch for Signal Routing (Input 1 can be routed directly to Output 1), Dimensions (W x H x D): 190 x 80 x...

www.thomann.co.uk

 

[Settembrini]

If the impedance of RCA Signal->XLR2 ≈ RCA GND->XLR1 and XLR1->XLR3 ≈ 2x the above, then it's likely that the construction is as advertised.

Since I have the Monoprice 104777 cables I have measured this out of curiosity (in a rather sloppy fashion I must say, since I had never used a multimeter) and found no difference in these values (the Multimeter indicates "00.3" at 200Ω in all three measurements)

 

[staticV3]

Since I have the Monoprice 104777 cables I have measured this out of curiosity (in a rather sloppy fashion I must say, since I had never used a multimeter) and found no difference in these values (the Multimeter indicates "00.3" at 200Ω in all three measurements)

Your multimeter may lack the precision for meaningful measurements in this case.

If you're curious, something like the YR1035/TR1035 would be ideal, though I can fully understand if you cannot justify the cost.

Another, way cheaper way to confirm the cable construction would be to screw off the metal sleeves of the RCA and XLR plugs and inspect which wire colors go where.

 

[Settembrini]

Your multimeter may lack the precision for meaningful measurements in this case.

Yes that totally makes sense
Thanks for your response

 

[Settembrini]

Another, way cheaper way to confirm the cable construction would be to screw off the metal sleeves of the RCA and XLR plugs and inspect which wire colors go where.

I have opened the rca plug, here are some photos.
In regard to the XLR I took out the screw but could not find a way to take out the carcass and access the connection itself - I gave up cause got afraid of damaging it

 

[staticV3]

I have opened the rca plug, here are some photos.
In regard to the XLR I took out the screw but could not find a way to take out the carcass and access the connection itself - I gave up cause got afraid of damaging it

That looks like coax wiring to me, which in turn would mean that the cable construction cannot be as claimed:


Edit:
Or is that a second, white wire? Hard to tell.


If so, then the construction should be as claimed.

 

[Settembrini]

That looks like coax wiring to me, which in turn would mean that the cable construction cannot be as claimed:
View attachment 425439

Thanks for your answer!
Yes that is indeed a second, white wire - the picture is unfocused. I took one pic from one side (black and silver cable) and from the other side (black and white cable)

 

[staticV3]

Thanks for your answer!
Interesting that a well known manufacturer could do something like this...

See my edit above. I judged prematurely.

 

[Settembrini]

See my edit above. I judged prematurely.

Yes I have also edited my answer, it remains possible for the cable to be as claimed.

 

[gilency]

This is a cable I just purchased in Amazon I was planning on connecting the Flex MiniDSP with 2 Rhytmik LV12M subwoofers. It has the connections as recommended a few comments ago. I guess it could work for you too.

Amazon.com

 

[Miguelón]

This is a cable I just purchased in Amazon I was planning on connecting the Flex MiniDSP with 2 Rhytmik LV12M subwoofers. It has the connections as recommended a few comments ago. I guess it could work for you too.

Amazon.com

View attachment 428771

Thanks for your intention to help, but this is precisely the wrong type of cable. Wrong from the point of view of protection against loops and interferences, otherwise will be fine.

Notice that 1 and 3 are joined on the input side and travel together on the shield, so any interference will be mixed.

I let you the scheme that allows to half the protection of a balanced connection:

Here the 3 pins go independently (2 wires plus shield) and 1 and 3 are mixed on the input side. It’s easy to be confused

For practice one just has to count the total number of wires inside the cable shield: 1 for wrong, 2 for right.

Nevertheless I end up with true balanced connection WiiM Ultra => Focusrite Scarlett 2i2 => Genelec 8030C because optimal tonality and by default sensitivity of the latest doesn’t work well with a direct DAC.

Thanks again!

 

[gilency]

I’m a newbie. Thank You for the explanation. I still need to find an adapter. Have 2 xlr cables already

 

[Miguelón]

I’m a newbie. Thank You for the explanation. I still need to find an adapter. Have 2 xlr cables already

Better get the Monoprice cable at Amazon, then connect the XLR extreme with your XLR cables as suggested by other member.

Amazon.com

 

[Speedskater]

In the figure in post #54
The shield doesn't need to be attached to the RCA connector.
(this may reduce ground loops)

 

[Miguelón]

In the figure in post #54
The shield doesn't need to be attached to the RCA connector.
(this may reduce ground loops)

I don’t understand: if reduces ground loops why doesn’t attach it to shield?

 

[Speedskater]

If the cable shield is only attached at the XLR end, it only acts as an extension of the metal chassis.
And there is no leakage/ground/noise current flowing thru it.

 

[Blumlein 88]

If the cable shield is only attached at the XLR end, it only acts as an extension of the metal chassis.
And there is no leakage/ground/noise current flowing thru it.

Bill Whitlock explains why he disagrees with you on this. With no ground connection you could have enough Common Mode voltage at the balanced end to overwhelm it. Grounding the shield at both ends and using a shielded twisted pair takes this possibility away. CMRR will be degraded by the output impedance of the source RCA end, but it won't be zero. Read section 2 in this document.

https://www.jensen-transformers.com/wp-content/uploads/2014/08/an003.pdf

As XLR's are typically use shielded twisted pair that is why you are well advised to use XLR cable right to the RCA end or use it and an XLR to RCA adapter at the RCA end. The diagram MIguelon showed is the better way. It does present the possibility of some current flowing and causing some hum, but other issues could be worse.