Correct way to connect an nCore XLR amp to an RCA source

[thanossapiens]

Hello, I am wondering if there is a safe way to do this, since most solutions I have found on the internet are about the connection of the xlr terminals to the internals of the amp, or something. I want to connect the nc400 to an old unbalanced tube pre amp.
Will something like this be ok, perhaps?
Before anyone says "just throw the t*be stuff away and find a balanced source", I already have balanced dac-preamps, I just want to try this for whatever reason.
Thanks in advance.

 

[NTK]

Welcome to ASR!

The method is described in detail in the NC400 datasheet, page 17, section 9.4.
https://www.diyclassd.com/img/upload/doc/ncore/nc400/Documentation/NC400_04xx.pdf

An example of an RCA to XLR converter cable implemented per the Hypex recommendation is:
https://www.amazon.com/Monoprice-XL...ca+to+xlr&qid=1612797435&s=electronics&sr=1-4

 

[thanossapiens]

An example of an RCA to XLR converter cable implemented per the Hypex recommendation is:
https://www.amazon.com/Monoprice-XL...ca+to+xlr&qid=1612797435&s=electronics&sr=1-4

• An XLR to RCA cable converts a balanced Audio signal into an unbalanced signal.
• This is good for sending Audio signals from an XLR source to an RCA input, or vice versa. Regardless of direction, The result will be an unbalanced signal.

It doesn't seem like it will be suitable, I think?

 

[AnalogSteph]

I would trust the pinout / schematic more than the description in this case.

This cable would not be suitable for converting most balanced outputs to unbalanced, just a handful that happen to be transformer-coupled or floating. For RCA to XLR it's just right, however.

 

[NTK]

Here is a clip from a more detailed application note from Hypex. There is little problem connecting an RCA output to an XLR input. (But please be aware that standard RCA outputs typical is half the voltage of standard XLR outputs. So make sure you have enough gain in the amplifier with the XLR input.) However, you should not do the reverse. Because it shorts one leg of the output to ground.
https://www.hypex.nl/img/upload/doc/an_wp/AN_Legacy_pin_1_problems.pdf

 

[thanossapiens]

Here is a clip from a more detailed application note from Hypex. There is little problem connecting an RCA output to an XLR input. (But please be aware that standard RCA outputs typical is half the voltage of standard XLR outputs. So make sure you have enough gain in the amplifier with the XLR input.) However, you should not do the reverse. Because it shorts one leg of the output to ground.
https://www.hypex.nl/img/upload/doc/an_wp/AN_Legacy_pin_1_problems.pdf

I do not understand the technical stuff so well, so I have 2 more questions just to be sure.
What do you mean by the reverse?
And, if I understand correctly, *any* RCA to XLR cable will be ok with these amps?
Thanks for your time

 

[NTK]

I do not understand the technical stuff so well, so I have 2 more questions just to be sure.
What do you mean by the reverse?
And, if I understand correctly, *any* RCA to XLR cable will be ok with these amps?
Thanks for your time

1. What I meant was it is OK to have an RCA output feeding into an XLR input. But it is usually not OK to feed an XLR output into an RCA input (with a simple adapter cable).
2. Not all RCA to XLR adapter cables are the same. They need to be wired according to the Hypex schematic for optimal performance. If in doubt, just simply order the Monoprice cables. But please make sure the connector genders are correct.

 

[AnalogSteph]

With XLRs, male is an output and female is an input, so the Monoprice cable would be the correct direction.

For this reason, you can also daisychain XLR-XLR cables to your heart's content right out of the box, they are always female to male. A feature that is no doubt appreciated by roadies and studio techs.

 

[thanossapiens]

Is this the same cable?

 

[NTK]

Is this the same cable?

Yes.

 

[thanossapiens]

I got them, although I cant help but think that amps like these would benefit from more "expensive" cables

 

[NTK]

I got them, although I cant help but think that amps like these would benefit from more "expensive" cables

If you want to spend more money, you can also get buy directly from Hypex.
https://www.diyclassd.com/product/cable-set-interlink-st-rca-xlr-m-0-75m/147

Personally, I'd find it more rewarding to donate the difference to ASR, Erin's audio corner, and/or your favorite charities.

 

[thanossapiens]

Have any people here done any ABx tests with Monoprice cables? The ASR sentiment is that all cables are the same(sonically) I assume?

 

[Doodski]

Have any people here done any ABx tests with Monoprice cables? The ASR sentiment is that all cables are the same(sonically) I assume?

Decent cables do not change the sound. Snake oil cables change the sound. Any decent cable like Monoprice or Blue Jeans will sound the same.

 

[thanossapiens]

I see, thanks for the help guys!