He guys, someone brought to our attention that there is concern here. Let me pitch in.
Indeed, the outputs are balanced on the HiFi-M8, as we've said all along. That's still the case and it's not inconsistent with our marketing. The proper way to say that is that they are "impedance balanced." This means that the output impedance on L+ and L- pins (as well as R+ and R- pins) is same and neither wire is directly connected to ground.
On the contrary, with an unbalanced connection (typical three pin headphone connection), the common wire is connected to ground, where the impedance is lower. What happens is the signal that goes out to the headphones travels through a path with one impedance and the signal coming back on the common wire travels through a path of a different impedance. Such circuit is invariably more susceptible to common mode-induced electomagnetic interference and results in more noise.
Our circuit creates a balanced transmission line between the 4 pin output and the headphones. This minimizes common mode interference and results in a cleaner signal with lower noise floor and higher linearity.
Internally, the signal path varies from balanced to unbalanced, depending on engineering decisions at each stage. Our position is that short, well-shielded cable runs do not require a balanced connection, because interference is minimized by shielding. Inside the HiFi-M8'a PCBs, every trace is enveloped in a protective ground layer that together with our stringent RF protection circuitry isolates the trace and practically eliminates interference.
The real problem is not inside the unit, but outside the unit, where signal travels through headphone cables that are 1) long and 2) most of the time unshielded.
In order to combat the electro-magnetic interference on the Headphone Cable, we created the impedance-balanced outputs and they do their job very well. We have never heard complaints of signal degradation with any headphones and many customers prefer the balanced connection for this very reason.
Another potential benefit of a balanced output is the ability to drive twice as loud of a signal. We are giving you that same double output level, but not via a dual line driver, but rather with a single-ended line driver that runs off of a higher supply voltage (+/-10V DC). Two benefits here -- lower distortion AND lower power consumption.
A balanced high-current line driver would require twice as much power and would run the battery down in no time at all, so what we have created is a sound engineering decision -- you get the best of both worlds -- you get loud signal AND balanced lines to your headphones.
These battery-powered devices are tricky to get right, especially with high power outputs and I think that we have struck the right balance, as HiFi-M8 was recently placed on the Wall of Fame at the prestigious Innerfidelity publication, in addition to rave reviewed from many respected industry pubs. We've never heard complaints about the products' sound from our customers. Everyone loves the sound of their HiFi-M8.
If someone got confused with the terminology used on the website, we apologize. This is a complicated subject to put succinctly into marketing collateral.
Let us know if you have any questions. You can email me directly through the CEntrance website.
