InFlamesIt's what you would expect from something this small...depending on your source and its volume potential, I would say this is really just for very efficient headphones and IEMs. It's not going to drive anything power hungry or high impedence properly. Efficient 16 or 32 ohm headphones are a go. Anything higher and you should get something more appropriate.
InFlamesReally depends; I have no experience with iems above 16ohms. Closest comparison I could draw would be my KSC75s at 64ohms, to which I would say they are do-able but I feel my Q1 does a better job of course...but that's comparing 32mw to 190mw, haha.
If you already own these IEMs, try running them through your cell phone and see how the volume is. If you're good with it, then the Zuperdac S should be a little bit of an improvement over that, naturally.
Hopefully somebody else can chime in with a direct answer, but I would think that you would be fine.
InFlamesHey I'll put it this way...using the bundled AKG branded IEMs, I run them about 2 clicks from max to max, and my KSC75s HAVE to be maxed and even then I don't feel they're "right"...terrible dac/amp on this phone.
With the Zuperdac S connected and maxed out, I gain about 2-4 clicks of volume headroom...2 or 3 for the 64ohm KSC75s, which sound properly juiced now, and then 3 or 4 clicks for the AKG buds which also benefit a ton in every way.
I'd say you're good up to 64ohms in terms of portable-designed IEMs or headphones...just don't go running any Planars or anything too large with it expecting gold.