[eclein]

I never understood the balanced thing, other than using whats close to low z connectors I have no clue. What am I gonna hear if I get a balanced portable headphone amp as opposed to a regular??

Is balanced THE way to go??


wasn't sure where to post this question, move if you need to

[Speedskater]

Balanced interconnects are one thing, a balanced portable headphone amp is another.
Let's not get the ideas co-mingled.
For longer interconnects, balanced is better.
For thoughts on headphones, I'd go with this guy:  http://nwavguy.blogspot.com/

[avahifi]

Balanced line connections use three conductors per channel instead of the normal two conductors of standard interconnect cables.

The standard interconnect is normally a coax design, with a center hot conductor and and outer ground/shield conductor (one cable per channel).  The typical connection is with RCA plugs and jacks.

Balanced line uses three conductors per channel, a plus signal, a minus signal, and a shield/ground that does not carry audio information.  The advantage is that with long cable runs in an electrically noisy environment, such as a live stage or a studio packed with electronics, balanced line allows any hum pickup to cancel when the signals are summed to standard single ended use internally in the components.

There are three ways to take advantage of balanced line cables.

The first is to make the conversion to single ended with a small transformer at the inputs and outputs of the active units.  Much professional equipment is done this way. The transformers must be of very high quality to avoid rolling off the audio response.

The second way is to use active summing circuits at the inputs and outputs of the equipment connected by balanced line cables to achieve the same summing effect.  Again the electronics in the summing circuits must be of very high quality.  Note that no summing circuits at all probably are better than any type of summing circuit, especially if the use did not require balanced line cables in the first place.

The third way is to never sum the plus and minus signals at all!  This can be done by keeping four separate channels of electronics all the way from the source to the speakers, and finally sum the plus and minus signals at the speaker terminals.  This will keep exterrnal noise pickup at a minimum and also significantly reduce any common mode distortion from the electronics themselves, as it will all cancel at the speakers.  Unfortunately this method essentially doubles the cost of the electronics as four great channels are needed everywhere instead of the normal two.

Keep in mind that the conditions for need of balanced line connections, a noisy stage or rows of jam packed electronics racks in a recording studio do not exist in a home audio system.  It can be kept very quite and happy with the use of much less expensive well engineered two conductor standard cables.

Thus we would suggest that balanced line operation in a home audio system is redundant at best, and more costly, and perhaps even poorer performing as it must have extra summing circuits of some type.  We mentioned before that probably no need for extra summing circuits at all is probably a better choice.

Note that we can provide our equipment with balanced line inputs and outputs, but we recommend against that as we can identify no sonic advantage to paying the extra cost in a home audio environment.

Finally, in your choice of a headphone amp, pay more attention to the actual musical quality of the amp than if it is a balanced design or not.  It is the overall execution of an audio design that provides the quality, not claims for features, materials, or bells and whistles.

Regards,

Frank Van Alstine

[neekomax]

Thanks so much for the fantastic, easy to follow explanation. It's a rare thing in this hobby, I find.

[eclein]

Frank--Thanks for taking the time and explaining the whole thing, and in a concise and easy to understand way-I really appreciate it!!

[Speedskater]

Frank, a balanced interconnect circuit has two conductors!  A plus signal, a minus signal.  The shield is not part of the audio signal circuit, it should only be connected to the chassis at the connector(not the audio circuit ground).  The shield does not in all cases need to be connected at the receive end (but most of the time it's a good idea to connect it).

[JLM]

Keep in mind too that most home audio equipment that has balanced connectors do not have balanced designs internally, so they've probably used one of the methods to convert as Frank points out which can compromise the sound.

OTOH there are sources for inexpensive balanced cables, which are nice for providing a secure/quick connection without great force required.  And occasionally some equipment (like the 1st generation Eastern Electric DAC I had) reportedly sounds better using AES/EBU digital input (which is a balanced style connector).  Check out Scott Endler for very inexpensive custom interconnects/cables.

[Speedskater]

JLM, if I change a few words, I can repeat my previous post:

Balanced interconnects are one thing, a balanced internal circuit is another.
Let's not get the ideas co-mingled.

If the balanced interconnect solves  a problem, then the gains far outweigh the cost of the added circuit.

Changing a few more words:

Analog interconnects are one thing, digital are another.
Let's not get the ideas co-mingled.

[Speedskater]

If all of your equipment is:
1] Located in one small area
2] All your analog interconnects are short, let's say less than 6 to 10 feet (2 or 3 meters)
3] All the AC power comes from one outlet
Then the gains from balanced interconnects will be minimal.

But if your
1] Amps are remotely located at the speakers
2] Your analog interconnects are long
3] Your AC power comes from 2 or more separate outlets
Then balanced interconnects are a good idea.

[Speedskater]

I should note that "NwAvGuy" who does a lot of good headphone related equipment tests and designed a great DIY headphone amp, shares Frank's opinion.

http://nwavguy.blogspot.com/

"NwAvGuy" writes:
Balanced audio is great for pro use with long cables and electrically hostile environments. But it’s generally more of a liability than an asset in home audio gear. All else being equal, balanced stages usually have higher overall noise and distortion than their unbalanced counterparts. Headphone drivers don’t magically somehow work better when driven by a balanced source. Most of the stuff you hear and read about balanced audio for home headphone gear is myth, hype and even snake oil.

[ajzepp]

Finally, in your choice of a headphone amp, pay more attention to the actual musical quality of the amp than if it is a balanced design or not.  It is the overall execution of an audio design that provides the quality, not claims for features, materials, or bells and whistles.

Regards,

Frank Van Alstine

Hmmm....I bet a Van Alstine headamp would sure sound nice! (hint, hint)