Well I bit the bullet based on some favourable remarks about the new sound and encouraging descriptions of the installation process on Head-Fi and I went ahead and ordered the so-called Uber upgrade for my Schiit Bifrost DAC.
The Schiit web site describes the upgrade thus "This DAC/Analog upgrade card improves the sonic and measured performance of Bifrost, using a discrete, direct-coupled gain stage from Gungnir. This discrete stage is more sophisticated than the base Bifrost, with a more complex topology, and DC servo to eliminate capacitors in the signal path. The Bifrost Uber Analog card can be ordered with any new Bifrost at a cost of $70, or purchased as an upgrade for $100."
I was not altogether unhappy with the existing sound of the Bifrost and I wasn't quite sure what to expect. Further, I had to consider the added cost of postage to Australia, which reduces somewhat the bargain nature of this upgrade. So it was with some uncertainty about the worth of it all, I followed the instructions here http://www.head-fi.org/t/661444/schiit-bifrost-uber-analog-upgrade/15 and regarding the screws, here http://www.head-fi.org/t/661444/schiit-bifrost-uber-analog-upgrade/60 to insert the new board which arrived promptly and in good order today.
Thanks to "toschek" and "sceleratus" descriptions, I managed to install the board easily within 20 minutes (including time to find the right screwdriver!). Yes, the little LED lights were tricky but they actually slid into the holes with a minimum of fuss once I held the boards at the right angle.
I know I should give the new board some time to "mature" but I could not help myself. The music came on. I can't do an A/B comparison but I think some differences were immediately noticeable. The sound was smoother and fuller. That was even without sitting down to contemplate. Once I did, I came to appreciate that an initial perception of fullness was more about a better defined sound stage with instruments sounding balanced and "more in their places". There is also a greater sense of richness which may reflect a more detailed presentation but certainly a little less harshness in the upper registers..... Some have mentioned better bass extension but of that I am uncertain. I would rather say, "a little thicker", if that makes any sense. Overall the sound seems more coherent, detailed and smoother but still with the characteristic energy that I liked about the Bifrost before. A few more hours of run-in will be interesting.
I did a short comparison with the aging NAD CD541 player and the comparative lack of harshness in the Bifrost was very noticeable.
In short, I think it has been a worthwhile upgrade. Cost wise, I suppose you will have to weigh it up for yourself once you factor in oversease postage (if that applies), but if you were buying a new unit, the Uber would definitely be the way to go.
Equipment used - NAD c541 CD transport, coaxial connection to the NAD 355BEE Amplifier , Ascension floor standers by Adelaide Speakers.
Friday update: The update has had some days to settle in now and sounds very nice... was there a little harshness in some recordings before??? Can't find it now, or was it my imagination? The words coherent, stable soundstage, detailed, smooth still apply and also apply to the wi-fi streamed mp3/4 files coming through my Sonos network.... Still plan to review the Chameleon vs Bifrost comparison when I have time (See previous post for updates).... Sit back, enjoy the music!