Why Balanced Headphone Amps? - Page 7

Quote:

Originally Posted by sbradley02 

Even there it is difficult if not impossible to remove the variables. You would need to have a 'balanced' amp and one that wasn't that were as close as possible to being identical in topology and specifications and this is challenging to say the least. Generally speaking, what people are saying is this 'balanced' amp is better than that conventional one which says nothing about the topology.

 

I suspect that much of the perceived benefits of 'balanced' is in the connector which eliminates the common ground lead, and not in the actual topology, yet you seldom hear of someone using that configuration with a conventional amp.

True.

And generally speaking you'll have those that say a SE amp sound better than balanced. CMRR/crosstalk are the only benefits to balanced yet you can tie the grounds

and use a 4-pin connector making the often more expensive balanced moot.

Quote:

Originally Posted by sbradley02 

Yes. I would love to see a comparison where people adapt a conventional amp to use the 4 pin connector and see what improvements there are, if any. Would also require rewiring the headphones so direct comparison is again a bit difficult.

I believe Alex will be doing this for the LF V2. And I also believe Steve Eddy will be adopting it

for his amp. Comparisons are flawed either way, unless you go through an extensive PITA

to set one up that's close to flawless. 

Ha ha ha ha.   All of my amps are balanced.  Some bridged (I think) and some differential.  Really can't tell the difference between the two.  However, the difference between SE amps is not in the sound sig IMO.  It's in the detail, resolution, soundstage and the control of the drivers ie.. tighter bass response IMO..

Quote:

Originally Posted by preproman 

Ha ha ha ha.   All of my amps are balanced.  Some bridged (I think) and some differential.  Really can't tell the difference between the two.  However, the difference between SE amps is not in the sound sig IMO.  It's in the detail, resolution, soundstage and the control of the drivers ie.. tighter bass response IMO..

You should learn what's behind your amps, prep. I don't believe neither Bradley nor I were talking about sound sig.

Yes. I would love to see a comparison where people adapt a conventional amp to use the 4 pin connector and see what improvements there are, if any. 

And I believe you only see significant differences when using a differential DAC.

Quote:

Originally Posted by paradoxper 

You should learn what's behind your amps, prep. I don't believe neither Bradley nor I were talking about sound sig.

 

Yes. I would love to see a comparison where people adapt a conventional amp to use the 4 pin connector and see what improvements there are, if any. 

 

And I believe you only see significant differences when using a differential DAC.

I'm pretty sure the M^3 and the CK2III is bridged.   Also both my DACs are differential..

Quote:

Originally Posted by preproman 

 

I'm pretty sure the M^3 and the CK2III is bridged.   Also both my DACs are differential..

IIRC they are in symmetrical operation, so differential. And yep, yours are.

Quote:

Originally Posted by sbradley02 

That was my original question...

 

I feel that no benefit was demonstrated for the amps that are usually referred to as balanced but which are really comprised of two separate amps per channel in a push-pull configuration, beyond a possible small benefit of eliminating the shared common, which can also be done with an "unbalanced" amp. True balanced amps, which are differential from input to output, are another story, but these are rare in the industry.

 

Others of course disagree

IMO.. The discussion in this thread seems like "base on the theory"... (eg. Balanced amp got from channel > supposed to sound better)

Does anyone try to compare balance and un-balance amp by listening them?

And I agree some reply above.. It sounds like a marketing technique. Balanced Amp > Better Sound > High End > More Profit!!!

In fact, high end product has way more profit than low end.

Quote:

Originally Posted by fmlfml 

 

IMO.. The discussion in this thread seems like "base on the theory"... (eg. Balanced amp got from channel > supposed to sound better)

Does anyone try to compare balance and un-balance amp by listening them?

And I agree some reply above.. It sounds like a marketing technique. Balanced Amp > Better Sound > High End > More Profit!!!

In fact, high end product has way more profit than low end.

Are you talking about comparing the two in strict listening test, or general subjective preference?

Also, what do you mean by high end product has way more profit than low end?  What example of low end vs high end.

Quote:

Originally Posted by paradoxper 

Are you talking about comparing the two in strict listening test, or general subjective preference?

 

Also, what do you mean by high end product has way more profit than low end?  What example of low end vs high end.

Say for example, Schiit earn $150 profit from every VALHALLA (low end) they sell while MJOLNIR (high end) has $350 profit..

Quote:

Originally Posted by fmlfml 

Say for example, Schiit earn $150 profit from every VALHALLA (low end) they sell while MJOLNIR (high end) has $350 profit..

I was thinking more along the lines of Schiit selling all products (thus far) for under $1k, but selling thousands, where as

other's may sell 1 or a few products in the range of $1k-3k, but their quantity is much less. Thus the low end product has more profit.

However I see your point, too.

I would to start a list of those who can switch between balanced and unbalanced on their rigs and what differences they hear.  Be sure to include your setup mainly the equipment, connectors, mode, and headphone.

Setup:

Amp:

Dac:

Interconnects:

Headphones:

Setup:  NA Blur

Amp:  Balanced Ultra Desktop Amp

Dac:  Grace Design m903

Interconnects:  Single ended and balanced TRS to XLR 3-pin

Headphones:  AH-D2000

How I switch between the two modes is by using the front panel on the m903 to switch between the balanced and unbalanced outputs.  I can channel volume match these via setting both to 90dB and saving.  I then switch between balanced and unbalanced inputs on the amp by front switch.  I have the volume down at zero when I switch so there is no perceived volume difference.  I turn the volume up after I conduct the switch and listen to various tracks.

I hear a clear improvement in the bass response and soundstage.  It is as if the driver is tightly controlled in balanced mode and a little sloppy and loose in single ended.

I admit I do not fully understand how each signal path is created nor how each stage is processed, but I do hear a difference.  It could be that in balanced mode the amp or DAC for that matter is doing more or even less processing than when it is in single ended ( unbalanced mode ).  Perhaps those that are more familiar with the electronics in each can describe how the two signal paths differ and whether a specific component / stage could change the sound in the way I describe.

I can say that I have read all of these concerns as well as benefits with balanced amps, but I am more concerned with either concrete measurements of what people hear rather than pure conjecture based on theory.  I will see if both Tyll Hertsens and someone from Grace Design will comment on the various topologies of the balanced vs unbalanced issue.  Perhaps then we will all understand how the signal may be different along the two paths.

Regardless I can say with certainty that the setup described above in balanced mode does sound tighter and more controlled than when in unbalanced mode.

Be sure to follow the setup template above and describe any measured or heard differences between balanced and unbalanced modes.

This being the Sound Science forum, I'm afraid you're going to have to do better than that.

se

Hi All,
This is a very interesting thread with lots of good discussion.  A few thoughts came to my mind while reading.  I know this is a bit of a tangent to the original topic...

In my opinion there should be no inherent difference between the sound qualities of unbalanced and balanced interfaces.  Instead, sound quality differences can be attributed to two factors:  
1) The topology and implementation of each driver/receiver circuit.  
2) The effects of noise pickup on each type of interface.  Note that there are two primary types of noise pickup on here.  Radiated noise from the environment (eg. iPhone in pocket) and conducted ground noise between the two devices.  

Properly designed balanced interfaces with good common mode rejection can effectively reduce both types of interference.  "Properly designed", imho, includes *differential* inputs!

I don't think that just because an unbalanced connection is short it will not be susceptible to noise.  Again, consider the two types of noise pickup.  Any two pieces of unbalanced gear that are connected together will have some amount of current flowing through the cable shied of the cable connecting them.  This will induce a noise voltage that will be picked up by the receiving end.  There will always be *some* ground potential difference between the two chassis. Even in designs that employ two prong power cords there will be some ground leakage.  This noise is not always obvious but is usually comprised of powerline related harmonics (60/120/240Hz)  Also, with the widespread presence of 2GHz radio stations in our pockets (iPhone and Blackberry etc.) even a short cable is a very effective antenna.  The home environment is now polluted with an abundance of intentional and unintentional radiators that were not present in the recent past.  GSM, CDMA, Bluetooth, Wi-Fi, switchmode power supplies, computers, capacitive touch screens, compact fluorescent light bulbs, flat screen TVs etc...  These in addition to the ever present 60Hz magnetic fields from your house wiring.  
All of this gets in to your audio at some level!  The question is will it be audible?  Some of these interference sources can be audible as unwanted noise, while others can manifest in more subtle ways which degrades the resolution of your signal.


In our m903 we provide both balanced and unbalanced interfaces in an effort to provide compatibility with a wide range of equipment.  In the case of the outputs there are two separate output amplifiers operating in parallel from the same internal signal source.  One is a simple single ended amplifier stage while the other is a fully differential balanced output driver.  However, the preceding stage in the m903 is single ended so the balanced output driver is also acting as a single ended to balanced converter.  The use of a fully differential amplifier topology helps ensure a high degree of symmetry in voltage and output impedance in the balanced output signal.  This is important for the differential receiver at the other end to have good common mode rejection.

I hope some of this makes sense!
Cheers,
Michael

Quote:

Originally Posted by sbradley02 

Yes. I would love to see a comparison where people adapt a conventional amp to use the 4 pin connector and see what improvements there are, if any. Would also require rewiring the headphones so direct comparison is again a bit difficult.

I'll preface this by stating that I have not converted one of our headphone amps to a four wire connection and listened...

But, my guess is that the crosstalk induced by that small portion of common ground is negligible.  Personally I prefer to listen to headphones with some sort of crossfeed circuit.  This is intentional crosstalk that is many orders of magnitude higher than what might be caused by a few milli Ohms of resistance in a common ground connection.  If the musical material does not benefit from a crossfeed circuit it likely does not have wide stereo information which makes crosstalk less of an issue anyway...