"Not Just a Dongle Anymore"
My Fulla 2 arrived two weeks ago and I've been testing it intermittently against my portable CD player (on Alessandro MS-1 and Sennheiser HD1 in-ear headphones with a 1/8" to 1/4" adapter). I am impressed by the fit and finish of the case and the visible parts. Looking at the case, I'd say it is actually overbuilt, since nothing else at this price level would be built this way – the heavy-duty metal case, perfectly polished knob, etc. would have been replaced with plastic equivalents in a comparable retail product. Everything is solid, lines up perfectly, and performs without any kind of noise, distortion, or coloration.
The volume knob is silent – the non-adjustable gain setting seems to work perfectly with both headphones (starting at 6 o'clock and going clockwise, my listening range seems to be from 7.5 to 10 o'clock, using just over the first quarter of full volume with quiet recordings). Most of my music is 320 kbps VBR AAC and I've also tested it with streaming audio. My early impressions of the Fulla 2 are that it has a neutral sound – nothing appears to be emphasized or tuned euphonically, and there are no extraneous settings or switches to change filters, etc. (as it should be).
On a subjective level, I think the Fulla 2 is capable of driving each headphone to its limit – obviously their volume limits, but more importantly, their ability to resolve detail and dynamics, pace, rhythm, timbre, and timing. My imaging impressions are limited by each headphone's design, so I'd like to hear from other people about head-stages from their headphones. I'll also test the Fulla 2 with some lossless material to see if it makes a difference (I suspect there won't be an audible difference). It easily passes the simplest and most important test: it makes me want to keep listening to more music.
I want to test its line-out DAC function (with an integrated amplifier) later. If I had the opportunity, I'd compare it head-to-head against the more expensive AudioQuest Dragonfly Red and Chord Mojo, as these were the other DACs I was considering. It's great with a laptop, I haven't tried it with a smartphone/digital player, and it might be a great outboard solution for somebody building a mini PC for a music system or 2-channel home theatre.
The Fulla 2 hasn't changed its sound signature since it arrived – I've just gotten more adventurous with the volume knob as I've put more listening time into the box. It never sounds strained or distorted as I increase the volume, I simply hit the limit of safe listening volumes for my ears very quickly. Also, channel matching on the potentiometer seems to be excellent even at the lower positions.
For $100, I don't think there is anything out there that sounds better.