Single-ended DAC to balanced amp to balanced/unbalanced headphone - still benefit?

[jaytrinitron]

Hey all,
Amir has previously stated that balanced outputs block ground loops and such, is it possible to still get the benefits of balanced outs with a single ended output from a DAC? Does my headphone cable have to be balanced also to get the benefits, or is it enough that I am plugging it into an amp with a fully balanced topology? What other benefits to balanced outputs offer, exactly, and are there better and cheaper ways to get these benefits?

Also, semi-related: I have read that the Massdrop THX AAA 789 is not truly balanced, according to the creators (THX says it would be very little benefit for a big increase in price), but is still "balanced enough" that it measures great and the balanced signal path works as it should. Would I get the full benefit of balanced outs using it?

 

[amirm]

Headphone cable or connection to the amplifier has nothing to do with the benefits of interconnecting a DAC and amp using balanced. And yes, if you have an amp with balanced input and can make a custom cable, you can get some of the benefits. If your amplifier does not have balanced INPUTS then there is nothing you can do.

 

[jaytrinitron]

Thank you for your response, Amir!

Headphone cable or connection to the amplifier has nothing to do with the benefits of interconnecting a DAC and amp using balanced.

Wait, then what are the benefits of interconnecting a DAC and amp using balanced, if the headphone is connected to the amp via balanced output anyway?

And yes, if you have an amp with balanced input and can make a custom cable, you can get some of the benefits. If your amplifier does not have balanced INPUTS then there is nothing you can do.

To elaborate, if I'm understanding this correctly, the amp output to the headphone must be balanced (hence the need for a custom cable), but the amp (which still needs to be balanced, i.e. have balanced inputs) input via the DAC can still be single-ended (however, you lose out on some benefit). What benefits would I be losing out on using this approach, vs. an entirely balanced audio chain?

 

[amirm]

Wait, then what are the benefits of interconnecting a DAC and amp using balanced, if the headphone is connected to the amp via balanced output anyway?

The headphone thing is a misnomer. There is no such thing as balanced and unbalanced headphone connections. They are all balanced since your headphones are not connected to the ground. This is an incorrect marketing term invented by someone.

To elaborate, if I'm understanding this correctly, the amp output to the headphone must be balanced (hence the need for a custom cable), but the amp (which still needs to be balanced, i.e. have balanced inputs) input via the DAC can still be single-ended (however, you lose out on some benefit). What benefits would I be losing out on using this approach, vs. an entirely balanced audio chain?

Just erase any concept of the headphone connection. That is only a benefit if the headphone amp puts out more power in balanced mode.

The input side is real: using a balanced connection to the input of the amp frees you from many potential ground loops. In computer audio you have a long chain of products with multiple power supplies which increases the possibility of ground loops. Using a balanced interconnect between the DAC and amp helps a lot to eliminate these ground loops. This benefit is there whether you use a balanced or unbalanced headphones connection.

 

[gr-e]

Using a balanced interconnect between the DAC and amp helps a lot to eliminate these ground loops

Can you please explain how balanced interconnects eliminate ground loops? They have a ground wire just like SE connections and I always thought they can only help with interference in wire.

 

[SIY]

The signal is not carried on the ground wire of a balanced connection. And any induced noise will be common mode between the two signal carrying wires and will thus be rejected, since a balanced input responds only to the difference in voltage between the two signal wires.

 

[gr-e]

Yeah, but the signal inside both devices is still referenced to ground

 

[SIY]

In engineered devices, that is not the same ground. There's a lot of confusion between signal ground, earth ground, and safety ground, and the common terminology does not help!

Here's a few references that might clear things up for you:

https://centralindianaaes.files.wordpress.com/2012/09/indy-aes-2012-seminar-w-notes-v1-0.pdf

https://www.accucalav.com/wp-content/uploads/2015/02/ground_loops.pdf

http://www.jhbrandt.net/wp-content/...tion_of_Balanced_and-Unbalanced-Equipment.pdf

https://www.diyaudio.com/archive/bl...d1460406090-bruno-putzeys-micropre-g-word.pdf

 

[jaytrinitron]

The headphone thing is a misnomer. There is no such thing as balanced and unbalanced headphone connections. They are all balanced since your headphones are not connected to the ground. This is an incorrect marketing term invented by someone.


Just erase any concept of the headphone connection. That is only a benefit if the headphone amp puts out more power in balanced mode.

The input side is real: using a balanced connection to the input of the amp frees you from many potential ground loops. In computer audio you have a long chain of products with multiple power supplies which increases the possibility of ground loops. Using a balanced interconnect between the DAC and amp helps a lot to eliminate these ground loops. This benefit is there whether you use a balanced or unbalanced headphones connection.

OK, so that all makes sense. So the only real benefit of balanced is with ground loops.

If this is the case, then ground loops are fairly easy to identify, are they not? They are immediately audible AFAIK so either you have an easily identifiable ground loop, or you don't. So if this is the case, if you do not hear the loud hum that a ground loop causes in a single-ended chain, then balanced offers no benefit, correct?

 

[AnalogSteph]

Pretty much so, but replace "loud hum" with "all kinds of extraneous noises". PCs, for example, have been known to be rather creative in that regard, depending on what kind of components are installed and how they are loaded. Some people started to be bothered by a ground loop only after installing a high-strung graphics card (and starting a game) or swapping out their power supply. I used to have a ground loop issue here, and the hum actually was one of my lesser worries.

 

[jaytrinitron]

Pretty much so, but replace "loud hum" with "all kinds of extraneous noises". PCs, for example, have been known to be rather creative in that regard, depending on what kind of components are installed and how they are loaded. Some people started to be bothered by a ground loop only after installing a high-strung graphics card (and starting a game) or swapping out their power supply. I used to have a ground loop issue here, and the hum actually was one of my lesser worries.

I see. But ground loops are always audible interference, correct? So I would not have to worry about the components (and ofc sound) if I can't hear anything obvious in a single-ended chain?

 

[Gomjab]

OK, so that all makes sense. So the only real benefit of balanced is with ground loops.

If this is the case, then ground loops are fairly easy to identify, are they not? They are immediately audible AFAIK so either you have an easily identifiable ground loop, or you don't. So if this is the case, if you do not hear the loud hum that a ground loop causes in a single-ended chain, then balanced offers no benefit, correct?

It also helps against external interference as the induced voltage of the interfering signal would effect both wires equally relative to ground but voltage difference between the wires would remain constant. Let’s call the two balanced wires wire A and wire B. If at one instance in time wire A measured -5V relative to ground and wire B measured +5V relative to ground the difference voltage measured between wire A and wire B would be 5V - (-5V) = 10V.

Now imagine an interfering signal induces 2V on the wires. It would effect both wires equally so we now have 5V + 2V - (-5V + 2V) = 7V - (-3V) = 7V + 3V = 10V so no change in differential voltage hence the external interference is rejected.

 

[Shoaibexpert]

Hi, I hope this post is not dead yet coz it's very relevant to my predicament. I am new to High End audio and have the Dragonfly Red (single Ended) DAC and have the Massdrop THX 789 Amp that has both balanced and single ended inputs and outputs.. My question is since the DAC is single ended, would connecting the DAC to the Dual XLR inputs of the Amp using a 3.5mm to dual Xlr cable (converter) make a difference n sound?

Also on the Headphone output side, I have the HiFiMan Sundara headphones which currently runs on Single ended cable, would buying and connecting a 4 pin XLR cable for the headphones benefit me over the stock single ended cable... Specifically in terms of sound quality (width, clarity, staging, depth etc.)

Just t out things in perspective, the cheapest and slightly reliable 3.5 mm to XLR cable is costing US$ 19 and the 4 Pin XLR headphone cable is costing US$ 50....need your help to find if this investment is worth it? Thanks guys!

 

[twsecrest]

Hi, I hope this post is not dead yet coz it's very relevant to my predicament. I am new to High End audio and have the Dragonfly Red (single Ended) DAC and have the Massdrop THX 789 Amp that has both balanced and single ended inputs and outputs.. My question is since the DAC is single ended, would connecting the DAC to the Dual XLR inputs of the Amp using a 3.5mm to dual Xlr cable (converter) make a difference n sound?
Also on the Headphone output side, I have the HiFiMan Sundara headphones which currently runs on Single ended cable, would buying and connecting a 4 pin XLR cable for the headphones benefit me over the stock single ended cable... Specifically in terms of sound quality (width, clarity, staging, depth etc.)
Just t out things in perspective, the cheapest and slightly reliable 3.5 mm to XLR cable is costing US$ 19 and the 4 Pin XLR headphone cable is costing US$ 50....need your help to find if this investment is worth it? Thanks guys!

Connecting the un-balanced (3.5mm) output on the Dragon Red to the balanced (XLR) input on anything (THX 789), will not offer any advantages.
I would to go for a balanced cable for the Sundara.

 

[solderdude]

Hi, I hope this post is not dead yet coz it's very relevant to my predicament. I am new to High End audio and have the Dragonfly Red (single Ended) DAC and have the Massdrop THX 789 Amp that has both balanced and single ended inputs and outputs.. My question is since the DAC is single ended, would connecting the DAC to the Dual XLR inputs of the Amp using a 3.5mm to dual Xlr cable (converter) make a difference in sound?

No, just use the RCA inputs. That is basically exactly the same as connecting the Dragonfly via a converter (cable) to an XLR input.

Also on the Headphone output side, I have the HiFiMan Sundara headphones which currently runs on Single ended cable, would buying and connecting a 4 pin XLR cable for the headphones benefit me over the stock single ended cable... Specifically in terms of sound quality (width, clarity, staging, depth etc.)

It will get you more headroom but the THX amp already has plenty to spare in SE mode.
The Sundara is dual entry so the returnwires are connected in the headphone plug so likely there will be no improvement in a technical sense.
However, if one convinces themselves there are benefits there may well be perceived differences but these are not originating from technical differences.

 

[Shoaibexpert]

No, just use the RCA inputs. That is basically exactly the same as connecting the Dragonfly via a converter (cable) to an XLR input.



It will get you more headroom but the THX amp already has plenty to spare in SE mode.
The Sundara is dual entry so the returnwires are connected in the headphone plug so likely there will be no improvement in a technical sense.
However, if one convinces themselves there are benefits there may well be perceived differences but these are not originating from technical differences.

Thanks @solderdude I wanted a bit more clarity on the HiFiMan Sundara construction you've mentioned...does this mean that using a balanced cable on the Sundara would not work and the Sundaras can't be used in true balanced mode? Some people have reported that using balanced cable improves the quality of audio like sound stage or depth/clarity. In truth, I don't need more headroom coz honestly speaking.. Even the preamp within the Dragonfly Red is enough to drive the Sundaras to around 95Dbs...which is more than enough more me. Also, I was wondering if the input processing by the THX amp would be different between the Rca and the XLR inputs making a difference....i don't wanna convince myself on any thing unless it's really proven by science. Thanks mate

 

[solderdude]

Yes, it can be used in balanced mode with a balanced cable but due to the construction of the SE cable there is no real benefit in a technical sense as the cable itself has 4 wires in it already.
Some single ended cables (the ones often used in headphones with a single entry on one cup only) have a 3-wire construction.
In those cases there could be technical benefits. But this is not the case here. The Sundara has a 4-wire cable.

You should only replace a cable if: A it is broken (makes poor or no contact for instance), B: you want a different length, C: you want a more supple cable, D: you need a different plug (can also buy a converter cable/plug instead) E: you want a different looking cable F: you have no idea what to spend money on. G: you need it to go louder on portable gear that has a balanced output.

The point I was trying to make is that one should not believe all that has been 'reported'.
People report clear audible differences even when there are none.
When one is to believe everything that has been 'reported', even by 'noted reviewers' one would have to buy all kinds of strange attributes, fuses, wall outlets, mains cables, filters, regenerative mains supplies, stones strategically placed on top of your amp, special sorbothane feet, the weirdest cables (with its pricing going all the way up to thousands) and what not. That all makes audible differences to some folks.
In this case the only benefit would be more output power in balanced mode which you don't need.

The RCA input = half the XLR input so there is no benefit of using the XLR input with a special cable (or converter plug) using half the XLR input. There are no magic components in the XLR plug... well the contact it makes is less cumbersome and the plugs look nicer.

You can save yourself some money here but it will always nag you when you hear something in certain recordings...
what if I would have bought a balanced cable... what if I ... in that case, at one point, you may try it anyway and most likely also report hearing differences.
That's the way the brain of all humans work. One rarely sees reports of sound deteriorating when people change a cable for the same reason. Usually there is always: more 'space', tighter bass, smoother this or that ...

In a technical sense, in this particular situation you can save money and be rest assured it wouldn't have made any difference despite positive reports.

 

[JohnYang1997]

Benefits of balance amp+headphone:
1, No more ground, there will be no common ground between two channel, better separation and less distortion due to crosstalk.
2, Double voltage swing. It's still true balanced even the headphones don't reference to ground. But the amp still do. The signal has ground, and two rails are referencced to ground. Gaining benefit of utilizing both rail the same time is meaningful especially for high impedance headphones. Quad the power output for high impedance.
3, Even harmonic and common noise rejection, the mains hum and even harmonics will be cancelled at least by a lot.

Down sides:
1, Doubled output impedance.
2, Doubled components.
3, Doubled area.
4, Doubled idle power consumption.
5, Increased thermal/resistance noise.

So in general the biggest benefit is higher voltage swing for high impedance headphones. Then it's the lower distortion and common noise cancellation.

However, due to many of the downsides, it's probably better to design a better single ended amp rather than balanced.

Real world instances, balanced output is suitable for portable application. Higher voltage swing from lower voltage rail. High voltage rail is harder to generate from batteries and the exponentially worse efficiency of boosting voltage is probably less ideal of just make a balanced amp. Easy 10V swing babe.

Also for full sized amplifiers, area and power consumption is not a concern. Balanced amp is easier to design and probably shows better spec like output power, distortion etc. Plus you can always (almost) balance an existing single ended design to make it look better. So this is also common.

So where to not design a balanced amp? BOM limited, area somewhat constrained, but high voltage rail is relatively easy to obtain. A good performing single ended small box that doesn't cost a fortune. Yeah you know what I'm talking about.

 

[Shoaibexpert]

Wow! @JohnYang1997...i can tell you know your stuff!

So from what you've said.. Apart from designing an amp...basically should I use the single ended or balanced on the input and output end of the THX Amp with the Sundaras and the HD650s whilst the DAC is single ended? No need for more volume here. Thanks

 

[Shoaibexpert]

Yes, it can be used in balanced mode with a balanced cable but due to the construction of the SE cable there is no real benefit in a technical sense as the cable itself has 4 wires in it already.
Some single ended cables (the ones often used in headphones with a single entry on one cup only) have a 3-wire construction.
In those cases there could be technical benefits. But this is not the case here. The Sundara has a 4-wire cable.

You should only replace a cable if: A it is broken (makes poor or no contact for instance), B: you want a different length, C: you want a more supple cable, D: you need a different plug (can also buy a converter cable/plug instead) E: you want a different looking cable F: you have no idea what to spend money on. G: you need it to go louder on portable gear that has a balanced output.

The point I was trying to make is that one should not believe all that has been 'reported'.
People report clear audible differences even when there are none.
When one is to believe everything that has been 'reported', even by 'noted reviewers' one would have to buy all kinds of strange attributes, fuses, wall outlets, mains cables, filters, regenerative mains supplies, stones strategically placed on top of your amp, special sorbothane feet, the weirdest cables (with its pricing going all the way up to thousands) and what not. That all makes audible differences to some folks.
In this case the only benefit would be more output power in balanced mode which you don't need.

The RCA input = half the XLR input so there is no benefit of using the XLR input with a special cable (or converter plug) using half the XLR input. There are no magic components in the XLR plug... well the contact it makes is less cumbersome and the plugs look nicer.

You can save yourself some money here but it will always nag you when you hear something in certain recordings...
what if I would have bought a balanced cable... what if I ... in that case, at one point, you may try it anyway and most likely also report hearing differences.
That's the way the brain of all humans work. One rarely sees reports of sound deteriorating when people change a cable for the same reason. Usually there is always: more 'space', tighter bass, smoother this or that ...

In a technical sense, in this particular situation you can save money and be rest assured it wouldn't have made any difference despite positive reports.

Thanks @solderdude for the detailed response.