A small comment on this.
I feel with some of you when it comes to the balanced portables, but I really question the need for balanced IEM's in portable application.
I even made my own portable balanced source to try it and yeah it has nice features, but on the whole it has issues. My little take on the idea had a 4-pin mini TRS and a switch where you went from balanced to unbalanced depending on the need. The problem here is that you are dealing with 2x's the parts (add another place if using a splitter to make unbalanced into balanced) when doing amps. That also means 2x's the power consumption.
Getting balanced sources is a problem if using standard devices. Many have a zero possibility and others need severe modifications. If using bluetooth like what I did you face an issue of software because not all phones have configurable data streams and some have badly written drivers, like the iphone. I phone has issues where its data stream is variable depending on tasks, low volume output compared to just about every other device out there, and on occassion likes to output distortion on top of the audio signal (a problem easily solved in play by hitting pause and starting again, but a unique and annoying problem nevertheless).
Now, if you are using an old iRiver with optical output, not much of an issue as most portable and non-portable DAC chips out there to make it easy on you by having balanced output. Plus, it also means that when doing the DAC design, you don't need to put in the Balanced to SE conversion (assumming that its not a V-out DAC using just a couple caps).
Here is the other thing........these are IEM's. Yes, the balanced armature style seems like it might benefit. The thing is really based on power requirements, etc. You don't need a lot to operate these and people have said that scaling up the power amount with these isn't what makes the difference. Then also look as what headphones out there are portable and would be worth going balanced for? The issue with portable audio has mostly been the sources since many of these portable amps sound wonderful on their own when presented with a proper load.
My motivation for balanced was that I wanted to try it and maybe doing so would allow me to bring some of my bigger, harder cans like Ortho's on the road because I could use more chips to generate more power and more slew rate (balanced) and power it by some lithium-ion's. In some cases it opened up whole new possibility for chips that had lower outputs, but were cleaner, smaller, and cheaper. Just look at some of the headphone/audio amp chips by TI, Maxim, and a few others.
But, despite all this.....I use my portable bluetooth dac as a single ended source.
Why?
Well, that way it all fits in my pocket.
If you would like to discuss this more with me further, please use a PM as I am rarely on head-fi. If you really want to make your own balanced IEM cables, I posted a simple how-to on my website. It is being converted to a DIY-instruction site. Just need to buy a camera with good macro so it has pic-by-pic. Woot for actual work taking time....
