^^ Thanks. I meant to include...in my OP...sorry if it's been asked and answered; but I didn't have time, to skim all 115 pages...lol.
Any thoughts, about the different models; in other words, what more amperage gets you...using it in this way?
Thanks
A laptop's USB 2.0 port can meet spec by providing only 500 mA of current at 5VDC, so the Concero would be more than satisfied with any of the Anker battery packs you've referenced, given that the weakest is rated at 2000mA, continuous. To me, the bigger issue is giving yourself enough capacity. The small one won't last long at driving the Concero between charging, so I would recommend this one, as a minimum capacity: http://www.ianker.com/product/79AN7903S-BA
The larger Anker battery could be considered overkill, but believe me, it gets old having to recharge the battery, and they will last a lot longer if you shallow-cycle them, rather than deep-cycling them between charges. In any case, for desktop use, I recommend keeping the battery pack connected to its charger with an AC outlet timer, like this one, that comes on every night to top off the battery when you're not using it, but off during the day: http://www.amazon.com/Intermatic-TN311-Heavy-Grounded-Timer/dp/B005MMSTNG
Regarding the "need" for using a battery pack in the first place: I believe the Concero has about the best power management/filtering of any USB-powered audio device that I've spent any time with. In my home, I've never actually heard any evidence of EMI or RFI coming in from the mains or from other appliances in our home, but our community does suffer some pretty severe brown outs (120V service dropping as low as 100V, at times - especially on summer afternoons, when everyone's running their air conditioners in the Texas heat.) I've also got a laptop (one of two) that itself generates enough noise at its USB ports, that I've been unable to use it with some other USB-powered ESS9023 DACs, like the JDS Labs Objective DAC - which, admittedly, can't compete with the Concero in terms of built-in power filtering. But the better of my two laptops, can itself manifest a power-related audible problem under certain situations (detailed earlier in this thread), that even the mighty Concero can't handle.
So... YMMV (depending on how clean your incoming power is, how noisy your household loads are, how noisy your laptop or PC is, how low a noise floor you're capable of achieving with other components in the chain, how transparent your headphones are, how clean your recordings are, etc.). But I know one thing for sure:
It's a lot easier to make a silk purse out of silk, than it is to make it out of a pig's ear - so why not give the Concero really clean power to begin with?
To me, "noise" is insidiously difficult to detect. You can be suffering its consequences with no awareness. As an analogy, when you look at a photograph that has insufficient Depth of Field (whether intentional on the part of the photographer, or not), it's very easy to distinguish those areas of the image that are "in focus" from those areas that are "not in focus" because you can see good areas and bad, simultaneously, right there in that one print. But the noise floor in audio is akin to diffraction in a photograph - the degradation of image quality is not only subtle, but also uniform across the entire image and, unless you have a second print (with less diffraction) lying right alongside the first print, it's next to impossible to even have an awareness that your resolution is compromised uniformly by noise.
I'm more content to let the Concero make its silk purse using silk.
Mike
