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Instead of connecting RCA preamp output to XLR pwrd speakers, could I use balanced 4.4 mm headphone jack to XLR?

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JanesJr1

JanesJr1

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Class A equipment that is designed for commercial use is allowed to produce more radio frequency emissions than Class B equipment designated for residential use. Your microwave won't cause your TV to flicker. But commercial microwaves in the office cafeteria might cause the same effect for your computer monitor!

Edit: My example was intentionally a bit fanciful. Just to be clear, any interference from a commercial microwave would be from the power supply not the heating radiation leaking out!

Oh, did I mention I work at a military installation with a big phased-array radar? Wonder if that could have something to do with it.... (kidding)
 

2ndHarm

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I have assumed that the noise is EM interference because it is intermittent or at least variable. It sounds like a distant, crackly halo around the signal, like a thin bit of wax paper stretched over a speaker cone. Maybe that's not a decisive diagnosis.

My speaker cable run is 2 meters. Interesting about the idea of using a single outlet: I assume that makes using a power strip for the amp, DAC, and two powered-speakers a good idea, just to prevent existing or new ground loop problems?
I noticed noise like that when using the output from my PC to drive my DACs. There was light background noise from the power supply - you could hear it going up and down as the computer consumed power, first for battery charging and then to run the CPU and other peripherals like memory, etc. Since many of those things run asynchronously the noise is variable. When I wanted things to be really quiet, I ran the computer on battery.
If that's the source of the noise, then running a balanced connection probably won't help.
That said, I always run balanced connections when available, just for the reduced chance of RF and EMF interference to my powered speakers. I used to occasionally pick up RF noise when the town police cars passed the house. I could sometimes hear them talking! My XLR connections killed that!
 

Vincent Kars

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could I instead run a balanced connection from the 4.4 mm jack to the speakers
No.
A normal balanced connection e.g. between a DAC and a AMP (most of the time XLR) is a 3 wire connection, you have a hot, a cold (the inverse of the hot) and a ground. At the receiver there is a differential amp removing all common noise.

What they call "balanced" in the headphone world is the ability to connect to a balanced amp, a push-pull design. This means L and R don't have a common ground as, due to the push-pull, the "ground" is active as well.
Hence you need a 4 wire connection L+/L- and R+/R-.
Nothing balanced about that, just 2 times single ended.

If you want to go balanced to your speakers, you need a DAC with a balanced line output.
Using the headphone "balanced" out is the same as using RCA, a 100% guaranteed unbalanced connection.
Bit more detail: https://www.thewelltemperedcomputer.com/HW/Headphone/Connect.htm
 
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JanesJr1

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No.
A normal balanced connection e.g. between a DAC and a AMP (most of the time XLR) is a 3 wire connection, you have a hot, a cold (the inverse of the hot) and a ground. At the receiver there is a differential amp removing all common noise.

What they call "balanced" in the headphone world is the ability to connect to a balanced amp, a push-pull design. This means L and R don't have a common ground as, due to the push-pull, the "ground" is active as well.
Hence you need a 4 wire connection L+/L- and R+/R-.
Nothing balanced about that, just 2 times single ended.

If you want to go balanced to your speakers, you need a DAC with a balanced line output.
Using the headphone "balanced" out is the same as using RCA, a 100% guaranteed unbalanced connection.
Bit more detail: https://www.thewelltemperedcomputer.com/HW/Headphone/Connect.htm
Thank you for the article on circuits, which summarizes the things I've been trying to pick up in bits and bytes elsewhere as I go along.

The 4.4 mm pentaconn headphone out jack is a TRRS connection, with 2 wires/channel plus ground, specifically for connection to balanced headphone cables, which I have already done for the purpose of getting some extra headroom for two inefficient headphones. Since I could connect pentaconn to XLR headphones, I wondered why I couldn't connect pentaconn to XLR jacks on powered speakers that lack unbalanced RCA jacks. But I didn't honestly know, so that's why I asked.

It's very helpful for me to think this through, so that I can understand it for future reference, so thank you!

What I infer from your comments and from the article, is that the TRRS pentaconn is not "balanced" in the same way that a 3-wire XLR (true balanced) powered-speaker jack would be, and therefore that the connection would be a mis-match of circuit topology. (Correct me if I'm wrong.) However, the circuit diagram for the pentaconn-to-XLR cable shows the pentaconn's + and - connections for L and R running to the respective #1 and #2 wires of the 3-pin XLR jack for each channel, with the common ground connected to the third pin. Just to validate: would that kind of connector work as a balanced line-out after all?

Now, as I said in a response to another forum member, I now wonder if this is necessary, even if it works. I can also just get less expensive RCA to XLR cables that would hook up the speakers in an unbalanced connection. Even if the alternative, pentaconn-to-XLR connection I proposed would work, I really don't need the extra power to connect to the powered speakers, as I might for the headphones. Also, I do have some noise here at my office and I don't know if it is EM interference or a ground loop thing: I suppose a "balanced" connection might prevent further problems there; but I don't have an end-to-end "balanced" setup anyway; just the quasi-balanced headphone jack on the headphone amp. So I'm tilted toward just using cheaper RCA-to-XLR cables, and crossing my fingers about the intermittent noise on the line.
 
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JanesJr1

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I noticed noise like that when using the output from my PC to drive my DACs. There was light background noise from the power supply - you could hear it going up and down as the computer consumed power, first for battery charging and then to run the CPU and other peripherals like memory, etc. Since many of those things run asynchronously the noise is variable. When I wanted things to be really quiet, I ran the computer on battery.
If that's the source of the noise, then running a balanced connection probably won't help.
That said, I always run balanced connections when available, just for the reduced chance of RF and EMF interference to my powered speakers. I used to occasionally pick up RF noise when the town police cars passed the house. I could sometimes hear them talking! My XLR connections killed that!
I will try to diagnose whether the problem occurs more with one laptop than another; or more with A/C than battery power. Thanks for a new angle on an old problem.
 

nagster

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I would like to connect my Topping A50s headphone amp to powered speakers, which have only balanced combo XLR/TRS jacks. The Topping's pre-amp out is unbalanced RCA, but it also has a balanced 4.4 mm headphone jack. Instead of running an unbalanced RCA-to-XLR connection, could I instead run a balanced connection from the 4.4 mm jack to the speakers' XLR inputs using this cable: I would like to connect my Topping A50s headphone amp to powered speakers, which have only balanced combo XLR/TRS jacks. The Topping's pre-amp out is unbalanced RCA, but it also has a balanced 4.4 mm headphone jack. Instead of running an unbalanced RCA-to-XLR connection, could I instead run a balanced connection from the 4.4 mm jack to the speakers' XLR inputs using this cable: https://www.amazon.com/4-4mm-Balanced-Headphone-Adapter-Silver/dp/B07WSRRN1X? Or are the levels or some other electrical attributes of the headphone jack unsuitable for such interconnection?
I've been using it that way for about 3 years. Conversion from 4.4mm/TRRRS to 2x XLR. No problem has occurred.
However, the sleeve of the 4.4mm jack of DMP-Z1 was floating, so I used the sleeve of the 3.5mm jack to ground it. The 4.4mm sleeve of the A50s may also be floating.
When not grounded, THD+N deteriorated by about 4dB.
dmpz1_trrrs_xlr.jpg
 

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JanesJr1

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I've been using it that way for about 3 years. Conversion from 4.4mm/TRRRS to 2x XLR. No problem has occurred.
However, the sleeve of the 4.4mm jack of DMP-Z1 was floating, so I used the sleeve of the 3.5mm jack to ground it. The 4.4mm sleeve of the A50s may also be floating.
When not grounded, THD+N deteriorated by about 4dB.
View attachment 207358
Thank you for the thorough and thoughtful reply. It's interesting to know that the 4.4 jack can be used this way. I'm more a novice on these things... When you describe your "2x xlr", it's also equivalent to a balanced 3 pin xlr connection, including your jump ground line to the 3.5mm jack, no? ...Just want to be sure I'm thinking about this correctly... Also, if I'm correct, the commercial 4.4M TRRS-to-dual 3-pin-XLR would have also worked, albeit at more expense, to provide a balanced connection, wouldn't it?

Also, I infer that the headphone jack's level and impedance are equivalent to an active speaker's line-in?

How did you measure THD+N? I wouldn't have thought to do that. What is the practical risk in a setup like this, mostly noise?

Back when I posted my question, I decided instead to use inexpensive but unbalanced RCA-to-XLR connectors and use my dac/amp as a switchable pre-amp for headphones and speakers, rather than have to unplug-and-plug at every switch. Plus, when I thought about it, I didn't really need a balanced connection for just a short-run line out to active speakers (cross my fingers on ground loop). I'm still learning how to think through my priorities on things like this...
 
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staticV3

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@nagster could you please upload the 997Hz sine file to Dropbox or GDrive and share it with us? I'd love to take a look.
 

Veri

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if I'm correct, the commercial 4.4M TRRS-to-dual 3-pin-XLR would have also worked, albeit at more expense, to provide a balanced connection, wouldn't it?
It doesn't solve the floating ground as far as I see. So you'll likely suffer from some additional distortion as @nagster has shown.

Back when I posted my question, I decided instead to use inexpensive but unbalanced RCA-to-XLR connectors and use my dac/amp as a switchable pre-amp for headphones and speakers
That seems like a most sensible solution ;)
 
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JanesJr1

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It doesn't solve the floating ground as far as I see. So you'll likely suffer from some additional distortion as @nagster has shown.
But since the 4.4mm TRRS to dual XLR connector has a ground to the 4.4MM shield, isn't that grounded back through the headphone jack? And (this a probably a very dumb question, my specialty) does a NON-floating ground require the shield to be connected all the way out to the XLR connectors? If so, wouldn't this special-purpose cable solution solve the floating-ground issue if properly designed?

I'd ask why the floating ground increases distortion, but I have a feeling the answer is beyond my pay-grade....
 

Veri

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I'd ask why the floating ground increases distortion, but I have a feeling the answer is beyond my pay-grade....
I have a nagging feeling the answer will be "it depends" on the head-amp implementation of the 4.4mm output :D
and of course proper construction of the cable used.
 

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I am poor at English. I don't know the subtle nuances. There may be a misunderstanding. In that case, please correct it.

Thank you for the thorough and thoughtful reply. It's interesting to know that the 4.4 jack can be used this way. I'm more a novice on these things... When you describe your "2x xlr", it's also equivalent to a balanced 3 pin xlr connection, including your jump ground line to the 3.5mm jack, no? ...Just want to be sure I'm thinking about this correctly... Also, if I'm correct, the commercial 4.4M TRRS-to-dual 3-pin-XLR would have also worked, albeit at more expense, to provide a balanced connection, wouldn't it?
First, the A50s ground and XLR pin1 must be connected.
If the sleeve of the A50s's 4.4mm jack is already grounded, a perfectly balanced output is possible with just the cable shown.
(However, neither your Amazon Link cable nor my cable seems to have a shield at the bifurcated part. I think it's only the drain wire.)
51bq5d5XUxL._SL1024_.jpg

If the sleeve of the A50s's 4.4mm jack is floating, you will need to connect the sleeve of the 4.4mm plug to the ground of the A50s by some means.
In the case of DMP-Z1, the sleeve of the 4.4mm jack was floating, so I grounded the sleeve of the 4.4mm plug via the sleeve of the 3.5mm jack.

Also, I infer that the headphone jack's level and impedance are equivalent to an active speaker's line-in?
I don't think the line input impedance of an powered speaker is equivalent to the A50s output impedance. I think it is extremely large when compared.
If you connect the headphone output and the line input, the output level and input level will of course be the same.

How did you measure THD+N? I wouldn't have thought to do that. What is the practical risk in a setup like this, mostly noise?
The output of the 4.4mm (+ 3.5mm sleeve) was measured by AP.

Back when I posted my question, I decided instead to use inexpensive but unbalanced RCA-to-XLR connectors and use my dac/amp as a switchable pre-amp for headphones and speakers, rather than have to unplug-and-plug at every switch. Plus, when I thought about it, I didn't really need a balanced connection for just a short-run line out to active speakers (cross my fingers on ground loop). I'm still learning how to think through my priorities on things like this...
Usually that's fine. I also use it a lot.
But this cable-only conversion is also a compromise.
For reference, one example of the best conversion when connecting from an unbalanced output to a balanced input is shown below.
View attachment 207392

You can't tell what the difference will be in the case of the A50 until you try it.
The A50s has a high performance balanced output. I think the theoretical best bet is to take advantage of this.
 

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JanesJr1

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But this cable-only conversion is also a compromise.
For reference, one example of the best conversion when connecting from an unbalanced output to a balanced input is shown below.
View attachment 207392

You can't tell what the difference will be in the case of the A50 until you try it.
The A50s has a high performance balanced output. I think the theoretical best bet is to take advantage of this.

Thank you for the explanation!

In this case, my cable solution was Monoprice RCA to XLR unbalanced cables to the active speakers that have worked well for several months. The ground is NOT floating in the circuit diagram. I have no idea what happened to distortion, but it sounds fine so far.

(And I at least take advantage of the balanced output with balanced connections to my three headphones.)
 
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