I'm taking a big chance, but I've 'invested' in the Geek Pulse X DAC with the Femto clock upgrade. Here's hoping a balanced DAC with dual ES9018K2M DACs will really make the HD800 shine when used with my impending Bryston BHA-1.
http://www.head-fi.org/t/687851/geek-pulse-geek-desktop-dac-amp-by-light-harmonics
It's still in campaign mode at Indiegogo but remember, it's a 'crowdsourced' product and might not ever be released. That said, Light Harmonics is well known for their DaVinci DAC and is about to release their first 'crowdsourced' product, the Geek Out in January, so my fears about spending the money now are pretty minimal. If anyone wants a referral from me during the last 12 days of the campaign, send me a PM.
A recent update from the LH Labs forum:
http://lhlabs.com/force/geekpulse/426-there-is-some-confused-people-out-there
I hope my answer can help you, but my primary language not English, grammar may be suck...
Geek Pulse X is full balanced design version of Geek Pulse
1. Geek Pulse X have XLR output connector (4 pin for headphone) on front panel and Dual XLR output connector (Daul 3-pin) for line out.
2. Geek Pulse X have Dual ES9018K2M dac chip inside, one dac chip for one audio channel decode
Geek LPS
1. Standalone product , Linear Power Supply
2. Main design for provide Pure Clear 12VDC Power for Geek Pulse / Geek Pulse X
(ps: Geek Pulse / Geek Pulse X have a Simply Power Supply in package, just buy it to upgrade the Power Supply system)
3. and have a USB in and USB out connector, to provide Pure Clear 5VDC USB power
(ps: you can google a word "iusbpower", it is same function of this product)
Geek Blue
1. Standalone product, Bluetooth 4.0 audio transfer.
2. Main design for connect a mobile to play audio using AptX technology.
(ps: It need Gavin/ Larry Ho to answer, if your mobile not have AptX technology, can it work??)
3. Geek Blue have a analog audio line out (direct connect active speaker or Amplifier) and Digital SPDIF output (connect DAC like Geek Pulse)
Femto Clock upgrade (Crystek Clock upgrade)
1. a parts call "Clock", using in Geek Pulse / Geek Pulse X
2. This upgrade will change a "very good clock" parts in Geek Pulse / Geek Pulse X, will change ONE SET (2 pieces) on each machine.
3. below USD$2000 price range DAC, In normal case cannot using this "very good clock" parts, because it's very expensive, need USD$60 UP per 1 piece.
Dale