• Registered: 2017-05-18
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Topic: AO4S-192 AIO to unbalanced input - what cable/adapter?

Hi,

I will be adding an AO4S-192 AIO to my HDSP 9632 PCI card. What is the best/correct way to connect two of the balanced outs of the AO4S to the (unbalanced) rca inputs of a headphone amp?

Will a simple TS (tip/sleeve, as opposed to TRS) to rca adapter (like the one in the link below) and an rca cable do the trick?

https://www.amazon.com/Hosa-GPR-101-inc … B000068O3S

Or, should I make a custom cable for this purpose? If so, what connections should it have?

I would be very grateful for an official RME reply here.

All the best,

Magnus

2 Reply by MC

  • MC
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Re: AO4S-192 AIO to unbalanced input - what cable/adapter?

The official reply is in the manual:

The electronic output stage does not operate servo balanced! When connecting unbalanced equipment, make sure the ring of a TRS jack is not connected. A conection of ring to ground (monaural jack) will cause an increase in THD (higher distortion)!

Regards
Matthias Carstens
RME

MC's Website

  • Registered: 2017-05-18
  • Posts: 42

Re: AO4S-192 AIO to unbalanced input - what cable/adapter?

MC wrote:

The official reply is in the manual:

The electronic output stage does not operate servo balanced! When connecting unbalanced equipment, make sure the ring of a TRS jack is not connected. A conection of ring to ground (monaural jack) will cause an increase in THD (higher distortion)!

Yes, thank you, I already knew this, but I don't understand what this means, exactly. For instance, can I use the TS to RCA adapter I linked to above? Is there any other kind of adapter readily available that I could use?

Or do I have to use a TRS jack and make the cable myself?

Best,

Magnus

4 Reply by MC

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Re: AO4S-192 AIO to unbalanced input - what cable/adapter?

Magnus wrote:

can I use the TS to RCA adapter I linked to above?

Yes, but sound performance might not be best. At least nothing will be broken this way.

Magnus wrote:

Is there any other kind of adapter readily available that I could use?

I am not aware of one.

Magnus wrote:

Or do I have to use a TRS jack and make the cable myself?

Best solution.

Regards
Matthias Carstens
RME

MC's Website

  • Registered: 2017-05-18
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Re: AO4S-192 AIO to unbalanced input - what cable/adapter?

Thanks Matthias, that's what I was afraid of (having to fashion the cables myself). Well, I like soldering, so I guess I will have to bite the bullet.

I don't want to compromise performance.

All the best and thanks again,

Magnus

  • Registered: 2017-05-18
  • Posts: 42

Re: AO4S-192 AIO to unbalanced input - what cable/adapter?

Sorry, Matthias, to be pestering you like this, but just to make absolutely clear: is it a cable like the Nr 10 in the link below that I need?

http://www.rane.com/note110.html

All the best and thanks again for helping me,

Magnus

  • vinark
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Re: AO4S-192 AIO to unbalanced input - what cable/adapter?

MC Am I nor correct in thinking if you use a TRS cable, properly wired, that at the unbalanced device, the ring will not touch the ground? That would mean you could also use a TRS cable. Would be easy to check too, by inserting a trs cable into the unbalanced device and see if the ring is shorted to sleeve at the other end.
Cheers and have a nice weekend.

Vincent, Amsterdam
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  • Registered: 2017-05-18
  • Posts: 42

Re: AO4S-192 AIO to unbalanced input - what cable/adapter?

vinark wrote:

MC Am I nor correct in thinking if you use a TRS cable, properly wired, that at the unbalanced device, the ring will not touch the ground? That would mean you could also use a TRS cable. Would be easy to check too, by inserting a trs cable into the unbalanced device and see if the ring is shorted to sleeve at the other end.
Cheers and have a nice weekend.

I need an RCA jack at the input though...

/Magnus

  • From: Houston, TX
  • Registered: 2007-05-11
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Re: AO4S-192 AIO to unbalanced input - what cable/adapter?

Magnus wrote:

Sorry, Matthias, to be pestering you like this, but just to make absolutely clear: is it a cable like the Nr 10 in the link below that I need?

http://www.rane.com/note110.html

All the best and thanks again for helping me,

Magnus

Yep - #10 is the configuration you need.  This will leave the "Ring" open at the AO4S-192 AIO.

If you really just don't want to make a pair of cables - you could also get away with buying a 1/4" TRS to L/R RCA cable (Stereo RCA's), and just use the left RCA on that cable (Right RCA would remain unconnected).  You'd need two of those cables though, and use the Left RCA (connects to TRS "Tip") on each one...

cool

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  • Registered: 2017-05-18
  • Posts: 42

Re: AO4S-192 AIO to unbalanced input - what cable/adapter?

Thanks Randyman, for clearing this up for me. And thanks for pointing out the other cable option. I will probably solder my own, though.

I appreciate the clarity of your reply!

Best,

Magnus

11 Reply by MC

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Re: AO4S-192 AIO to unbalanced input - what cable/adapter?

Magnus wrote:

Sorry, Matthias, to be pestering you like this, but just to make absolutely clear: is it a cable like the Nr 10 in the link below that I need?

http://www.rane.com/note110.html

Yes.

Regards
Matthias Carstens
RME

MC's Website

12 Reply by MC

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Re: AO4S-192 AIO to unbalanced input - what cable/adapter?

vinark wrote:

MC Am I nor correct in thinking if you use a TRS cable, properly wired, that at the unbalanced device, the ring will not touch the ground? That would mean you could also use a TRS cable. Would be easy to check too, by inserting a trs cable into the unbalanced device and see if the ring is shorted to sleeve at the other end.
Cheers and have a nice weekend.

Unfortunately you can not predict the design of the TS jack in the receiver.  It can well be that it is a TRS where R has intentionally be connected to ground.

Your proposal with the insert cable is nice.

Regards
Matthias Carstens
RME

MC's Website

  • Registered: 2017-05-18
  • Posts: 42

Re: AO4S-192 AIO to unbalanced input - what cable/adapter?

MC wrote:
Magnus wrote:

Sorry, Matthias, to be pestering you like this, but just to make absolutely clear: is it a cable like the Nr 10 in the link below that I need?

http://www.rane.com/note110.html

Yes.

Thanks, Matthias, great. I will be getting down to some soldering then!

BTW, is it a typo in the AO4S-192 manual where it says under specifications:

"Output: 4 x 1/4" TRS jack, servo balanced"

and then, further down in the section you quoted originally

"The  electronic  output  stage  does  not  operate  servo  balanced!"

This sounds contradictory to me. If both statements are indeed correct, then what does the second statement mean? And what is the topology of the balanced outputs of the AO4S-192?

Best,

Magnus

14 Reply by MC

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Re: AO4S-192 AIO to unbalanced input - what cable/adapter?

Yep, as so often many years un-noticed. I fixed it and uploaded the corrected versions (balanced).

Regards
Matthias Carstens
RME

MC's Website

  • Registered: 2017-05-18
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Re: AO4S-192 AIO to unbalanced input - what cable/adapter?

MC wrote:

Yep, as so often many years un-noticed. I fixed it and uploaded the corrected versions (balanced).

Funny! Back in the early 1980s, I studied sanskrit at a university here in Sweden. One of our exercise books was from the late 19th century (yup!) and I discovered a typo in one of the texts that had gone unnoticed for over 100 years. That impressed my professor. wink

Best,

Magnus