Hi all, my Quickstep is on the way, waiting hard next week!!! Can someone please advice, is the 9v vs 15v make any SQ difference to sensitive CIEM too?? I really hope not, because the priority of the Quickstep is entirely for my CIEM, and it is not very logic to feeding 15v for optimum performance vs portability. Please someone advice.
precsmo, good 9 volt rechargables will be just fine. That is all that I ever used with my Stepdance and the ES5.
Don't get me wrong. I love that Mike (zilchmod) and others pursue that extra edge, but especially for CIEM, you will be very happy not doubling or tripling the size and weight of the Quickstep. ;-)
You just bought a spectacular highly portable amp.
There is however, a very weak argument that could still be made for using 15V power with efficient IEMs: Datasheets for the OPA209 (or the original Stepdance' OPA1611) show that THD + Noise are taken to their lowest possible levels with a supply voltage (Vs) of 15. Go higher than 15Vs, up to the maximum permissible 18Vs, or lower than 15Vs, and according to the datasheets, these op-amps will suffer an increase in THD + Noise. In terms of measurable performance, they are at their cleanest when supplied with 15V, but I seriously cannot detect any difference in this regard, even with the Shure SE530. But, if you just want that warm and fuzzy feeling that comes with knowing you are driving the op-amps to deliver their absolute best possible performance, go for it. Personally, I don't think it's worth the effort and inconvenience - not at all.
Less efficient, full-size cans are a different story, entirely. I don't think anyone can claim they hear a reduction in THD + Noise at 15V, but a BUNCH of us can testify that we hear wonderful improvements in dynamics, bass energy and control - right up into the lower mids, when using something like the LCD-2 with the Stepdance family of portable amps running on 15V power. So clean, so neutral, so transparent - yet amazingly powerful, for such a tiny box. My DACport LX > 15V Stepdance > LCD-2 rev.1 comes very close to offering just as much PrAT and authority as my DACmini CX (1-Ohm mod) > LCD-2 rev.1, but I swear it's more neutral AND more transparent - it has none of the DACmini CX' very slight grain in the treble. It's also inky black in the absence of a signal - more so than any other amp I have or have had. The 15V Stepdance and its descendants can literally do double-duty as a desktop amp, for most purposes.