XLR to RCA cables or adaptors?

[Catweazle]

Hi there,
as my dealer made a generous offer by the end of last year I ordered a Klimax Exaktbox Organik to replace my Akurate Exaktbox. As the KEB has only XLR sockets, and my amp (C6100) has only RCA, the connection is an upcoming challenge to be solved. I have the luxury to own 3 pairs of each Linn Silver RCA, and Linn Silver RCA. So using either set with Neutrik adaptors would be one option. Another option would be to order custom built cables terminated by XLR on one end, and RCA on the other.

Any experience, what sounds best:
1. Linn silver balanced with adaptors.
2. Linn silver unbalanced with adaptors.
3. Linn silver (which one?) terminated with soldered connectors.

Obviously, I don't intend to rip the factory made cables. Thus option 3. would involve to buy cable from the roll and have it terminated by my dealer, anyway, and I'm free to order a convenient length. Am I right to assume, that the 1,20m length chosen by Linn is a good value for optimum length?

[ThomasOK]

Linn Silver unbalanced cabling with RCAs on one end and XLRs on the other.

[matthias]

Linn Silver unbalanced cabling with RCAs on one end and XLRs on the other.

Thomas,
how do you connect the three XLR pins to the unbalanced cable?
Thanks

[Catweazle]

Thomas,
how do you connect the three XLR pins to the unbalanced cable?
Thanks

I'm not Thomas, but I recall that Linn documented this somewhere in their docs:
https://docs.linn.co.uk/wiki/index.php/ ... 1_variant)

Thx to Thomas for his clarification.

[lejonklou]

The scheme in that document makes no sense to me.

There's a different connection required when going from an XLR output to an RCA input than the other way around.

On an XLR output, you definitely don't want to short the negative (cold) output to ground. That just makes that output feed unnecessary current to ground, which makes the circuit sound worse.

When it's the other way around, from RCA output to an XLR input, you do need to tie the negative (cold) to ground, to keep it quiet. In this case it's an input that reacts to a signal and as such shouldn't be left unconnected.

[Catweazle]

Not to connect the earth of the source to the cold RCA pin makes sort of sense to me. Do you suggest to keep the XLR output's earth floating? The earth potentials of both devices should be connected via the power cords anyway. Plugging them into the same power strip does help. What I don't know: Is the earth of the RCA device (the amp in my example) usually connected to the cold RCA pin, or does the RCA signal float with respect to the earth? Is there a standard for this?
When I look source first, a MC phono cartridge generates a floating signal in the first place for sure.

[matthias]

IIUC, from XLR to RCA Fredrik recommends to leave the negative (cold) XLR pin unconnected and to connect only positive (hot) and ground to the RCA.

[lejonklou]

Do you suggest to keep the XLR output's earth floating? The earth potentials of both devices should be connected via the power cords anyway.

No, signal ground must be connected. Chassis ground is something else.

Is the earth of the RCA device (the amp in my example) usually connected to the cold RCA pin, or does the RCA signal float with respect to the earth? Is there a standard for this?

The earth of the RCA is always connected to the earth of the XLR.

IIUC, from XLR to RCA Fredrik recommends to leave the negative (cold) XLR pin unconnected and to connect only positive (hot) and ground to the RCA.

Correct

[matthias]

IMG_2339.jpg

The earth potentials of both devices should be connected via the power cords anyway.

Every mains powered device has its own chassis ground. In an audio system signal ground and chassis ground are commonly connected in ONE point only (you see this point inside my power amp where both speaker returns meet with the chassis ground). With multiple connections you can get ground loops and hum.

[lejonklou]

There are many different chassis ground schemes.

Some connect signal ground directly to chassis ground. This easily creates ground loops.
Others connect signal ground to chassis ground through a resistor, to soften the impact of the ground loops.
I use floating ground, which means signal ground is connected to chassis ground with a little capacitance or not at all.

[matthias]

I use floating ground, which means signal ground is connected to chassis ground with a little capacitance or not at all.

Fredrik,
just for understanding:
Does not "ground" mean that both are connected somewhere to ONE ground in the case there is only one mains ground?
Thanks

[lejonklou]

I'm afraid I don't understand your question, matthias.

[matthias]

You say signal ground is NOT connected to chassis ground.
In the end there is one ground of the mains distribution.
So when both are "grounded" at a 0V potential, they must be connected somehow or do I miss something?

[lejonklou]

They don't have to be. That's why it's called floating - signal ground floats independently of mains ground.

[matthias]

Maybe it is one of the secrets that your devices sound so good, but I don't understand it, sorry.

[Catweazle]

IIUC, from XLR to RCA Fredrik recommends to leave the negative (cold) XLR pin unconnected and to connect only positive (hot) and ground to the RCA.

Correct

Ah, ok. I didn't quite get that. Now it makes sense!

[Defender]

its one of the secrets from Fredrik but he is not the only one who is doing it that way

I have also heard some use a thermistor to not directly connect signal ground and mains ground

[Peter Lanky]

Just to drift slightly off topic, but what was the original purpose of having the two different types of connector anyway? It seems the jury is out on which is best, so I would have thought that over time, one of them would have disappeared so as to standardise everything.

[Defender]

XLR is used in professional setups where you usually have much much longer cable lengths and a lot of chances for interferences. The intention is that outside influences (electrical fields etc.) are compensated out.
But the XLR /symmetric circuit design is more challenging and can create issues if they are not 100% symmetric or dont act 100% symmetric for example when temperatures change (temperature drift within the circuit).

In our home setups we most likely end up with the drawbacks of XLR technology and not having an advantage of the „benefits“.

[ThomasOK]

As Defender states the XLR connector and balanced cabling was/is the standard used for professional installations like recording studios, PA systems, etc. One big reason is that microphones generally only put out voltages similar to moving magnet cartridges which is pretty low. When you run these low voltages over microphone cables that can be 100ft long or longer you are likely to pick up hum, radio interference, etc. A balanced circuit puts out a signal on one wire that is in phase and a signal on another wire that is 180 degrees out of phase. At the receiving end the out of phase signal is flipped 180 degrees to make it in phase and combined with the in phase signal. Any noise and interference that is picked up on the cable should be on the plus and minus wires equally, so when the minus is flipped they will now be out of phase and will cancel each other out leaving just the music signal. This is all in theory. For the line levels and generally relatively short connections used in a home audio system this is really unnecessary.

Balanced/XLR is used on a lot of high end equipment but it carries problems with it. For example, to have a truly balanced preamp you would need twice as much audio circuitry with a + signal path and a - signal path from input to output. This is a higher level of complexity and would also need the + and - sections to be essentially perfect or when they are eventually summed you will get loss of musicality form the differences in the two signals. Anybody think there is such a thing as a perfect circuit out there? Me neither! There will always be some small differences between any two circuits and using them both to handle the same musical signal is going to reduce musicality. More musicality is likely to be lost by the additional circuitry that eventually sums the signals. (Unless it is actually sent balanced to the speaker, which I don't think is generally the case.)

Single ended, which for home audio mostly uses RCAs, is a simpler design and allows the fewest parts for the signal to traverse if you are a clever designer like Fredrik. Simple designs using few parts of the highest quality has always been the way to go in my experience. I believe Fredrik told me that one of the things about the Slipsik 7.1 is that it used the fewest electronic parts of any of his MM phono stages with the strictest tolerances on the components used. Of course in the case of Lejonklou HiFi every single part that goes into the design is listened to for the musical contribution it makes and that includes things like lock washers under the screws, the screws themselves (the ground screw on the SINGuilarity was just changed for a more musical one after significant research), the feet and even the washers between the feet and the cases on the large case units. Then these parts are all assembled onto precision circuit boards Fredrik designs using the best solder and the best temperatures for the solder joints (which varies with the mass of the joint) then assembled with the most musical torques on all the screws. This is the recipe for truly musical perfromance.

[matthias]

Interestingly Exposure use (or at least used in the past) XLR connectors to connect their devices unbalanced with only two of the three pins connected.

[ThomasOK]

Interestingly Exposure use (or at least used in the past) XLR connectors to connect their devices unbalanced with only two of the three pins connected.

That is unusual. Then again on the Linn LK1, LK2/LK280 and Isobarik Aktiv Crossover Linn used XLRs with Left channel on one pin, Right channel on another pin and ground on the third. I believe the claim at the time was that there weren't good circuit board mount RCA connectors and they were trying to minimize signal path and eliminate internal wiring and connections (there were short wires from the phono stage to the input RCAs). Linn went away from that design in later electronics from Kairn and Klout on forward. There have been numerous attempts to avoid RCAs and use other connectors by Hi-Fi companies. Naim gear with BNCs for phono input, DIN 4 an 5 connectors for inputs, outputs and connections to early power supplies and XLRs on power amps is one particular example. On the other hand early Naim electronics, particularly preamps, had a lot of internal wiring which means a lot of connections.

Technically the RCA isn't a well designed connector as it breaks the ground contact before breaking the hot which gives you that lovely loud hum when you unplug a connector from a live input. DIN and XLR connectors both break the hot contact before the ground so are electrically cleverer. But those are technical differences which don't necessarily mean they sound better. I don't know if Fredrik tested connectors other than RCA. But RCA is the overwhelming standard for home audio connection so compatibility is generally very good and the Lejonklou gear certainly sounds awfully good with RCAs.

[Nature]

Neutrik has an 3 pole female XLR to RCA adapter called NA2FPMF.

878-na2fpmf.jpg

If you use this Neutrik NA2FPMF adapter in combination with regular Linn Silver Interconnect, you will get exactly the same results as in this upper image under the heading XLR to RCA Connection Using Single Ended Cable.

XLR_to_RCA_Wiring.png

One can spend hours (have just done so) reading about this. My conclusion is that it seems most common to connect both pin 1 and 3 to ground.

Source of images and information:
https://www.neutrik.com/en/product/na2fpmf
https://docs.linn.co.uk/wiki/index.php/ ... Wiring.png

[matthias]

My conclusion is that it seems most common to connect both pin 1 and 3 to ground.

Yes, when you go from RCA to XLR but according to Fredrik not when you go from XLR to RCA.

[lejonklou]

One can spend hours (have just done so) reading about this. My conclusion is that it seems most common to connect both pin 1 and 3 to ground.

I haven't read anything. I have only used logic and listened to the two options of shorting or not shorting the negative output. The comparison was made using Linn equipment, but I don't remember which now, as it was at least a decade ago. As I expected, it sounded worse when shorting the negative output.

As you've read a lot about it, does anyone explain the reason why you'd want to short the negative output?