After digging out the Sennheiser HD-580s and by happenstance also encountering the manual I got with them 15 or so years ago, I got to wondering if there was much difference using them as balanced headphones. The iFi xDSD DAC has a TRRS connection, so it’s just a matter of getting a cable.
I put in an inquiry as to cost to have Amplifier Surgery build me a cable. They make good cables and use a silver-plated wire. I’ve been happy with their products before.
Anybody have any comments on going to a balanced configuration on the headphones?
It depends on the amp. If it’s not truly balanced amp, stick with regular trs and save the cash.
Schiit Jotunheim, it makes a difference. Eddy Current Black Widow 2, no difference. The ifi thingy… no clue if the balanced connection is there for convenience (which is what I suspect), or if they’re running truly balanced (doubt it), or doing some hybriy trickery and slapping the marketing fluff “S-Balanced” term on it just to sell more units (my second pick).
iFi’s “S-Balanced” is a dual-mono implementation that keeps the ground connections for each channel completely separate (vs. the 3-connector TRS jack which uses a shared ground). This legitimately, and measurably, reduces crosstalk between the channels.
The same is true with the iFi Nano iDSD Black Label, and many DAPs that claim “balanced” output.
So, yes, there’s an actual benefit to using a balanced cable with the xDSD and the HD5XX/6XX headphones (or any others that allow it). But it does not include getting more output power vs. staying “single ended”.
What this is not is a balanced-differential implementation. That would require two additional amplification circuits to provide an out-of-phase (opposite polarity) signal to the “ground” for each channel (which would now be a “negative” connection rather than just a “ground”). The effect of which is to double the output power (since now you’ve got, say a -2v to +2v swing instead of a 0v to +2v swing) and allows for common-mode noise rejection (not very relevant for headphone cables, but certainly so between sources, amplifiers, microphones and so on - that deal with much smaller signals), but it also doubles noise.
Balanced-differential still just requires the four connections.
And then there’s what @ProfFalkin is referring to. That’s simply taking a single-ended headphone connection - i.e. one shared ground and two signal lines, and using those to feed a 4-pin “balanced” connection. Which simply involves connecting that one shared ground to both ground pins on the 4-pin connector, and then using the signal lines as normal.
This is really just a poor use of the term “balanced”. “Dual mono, TRRS” would be a more accurate description. As this requires just two amplifier circuits (one per channel) not two (one per channel, per phase).
I successfully soldered my balanced cable for a newer Sennheiser HD model. Or so I hope…
Currently I use my RME ADI-2 Pro FS as DAC in the “Balanced Headphone Mode”. Connected with two TRS Jacks, to four channels in total let me hear fantastic new things. What stumps me is the fact, that the ground of the TRS shouldn’t be connected. RME doesn’t bring the grounding/shielding up their manual. Is that just right?
And my second question is: If I wish to connect two XLR female plugs to channel 1+2 (two DAC channels), what would be the right way to solder the respective connectors? I ask this, because I believe the connection written on the website is not correct for the plug on the right side. https://cdn.shopify.com/s/files/1/0362/2465/files/balancedamp.gif?v=1484086810
Yes, in balanced headphone output mode only the tip (+) and ring (-) connections are used on the TRS jacks. In most cases, there wouldn’t be anything to connect the shield to on the headphone side of things anyway.
Pin 2 is + (hot)
Pin 3 is - (cold)
Pin 1 is the shield
Depending on what you’re connecting it to, you may need to only connect pin 1 on the source (DAC) side of things. Pin 1 should go to chassis ground, but some gear connects it to signal-ground instead - which can result in ground loops/hum.
Best way to go is to start with Pin 1 connected to the shield on both ends, and if you get hum or noise then just cut the connection to pin 1 on the amp-end XLR connection.
The good RME guys just told me not to connect XLR plugs directly to my 300 Ohms headphones because of the difference in load. The DAC has 200 Ohms XLR output impedance. If one should wish to connect a futher amp (whatever the reasons are) this is the way to go.
I hadn’t realized you were thinking about using the XLR outputs to drive headphones directly, or I’d have advised against it too. They have a different output stage to the TRS jacks on the front with different characteristics - including the 200 ohm output impedance that you measure (vs. 0.1 ohm for the actual headphone connections).
