LH Labs LH-GP-GPU-001 Pulse DAC and Headphone Amplifier

I received my Pulse on the 26th of December and put it through it a preliminary listen ......... After loading the drivers onto my windows laptop I was time to give it a spin .................... All I can say is that I was quite stunned by its performance. It has an extremely low noise floor (inaudible to me) and delivers a clear,clean and dynamic sound. Highly detailed and very seductive. This unit has taken my mid-fi Sennheiser HD-598's to a totally new level of sonic bliss ....... Being that my headphones are relatively easy to drive the MID gain level is more than enough to make them sing. It is a very desireable unit and highly recommended .......... There is one caveat though ............... The Pulse DOES NOT have a analog input to allow you to use it as a straight headphone amp.With the inclusion of that function this unit would be close to perfect.

I own two Pulses, bought during the Indiegogo campaign: a standard (entry level) Pulse and a Pulse f/i which is closest to the Pulse Infinity, containing Femto clocks and an upgraded analogue stage, but the outputs are not balanced.Comparing the two, the massive difference is in the much more weighty sound of the Pulse f/i, which is clearly down to the improved analogue stage. It's a really beautiful, solid, warm and balanced sound. The entry-level Pulse is still excellent, but by comparisson sounds a bit colder. I'm sure that logically the Femto must add clarity and smoothness over the standard clocks, but I suspect it's much more subtle over the gains achieved by the analogue stage upgrade. You get what you pay for - although the analogue upgrade wasn't very expensive at all (the Femto clock upgrade was more of a price hike).The Pulse handles PCM up to 32-bit DXD, and DSD128 (DSD256 is supposed to be coming as a firmware update). I have only experienced resolutions up to DSD64 and PCM 24/192, and it handles both perfectly to my ear, having not a hint of digital harshness as long as the source material is of high quality (it will certainly reveal the sonic flaws in substandard digital material, particularly much stuff mastered in the early 2000's and earlier). My other gear is a Squeezebox Touch (modified to stream 24/192 and DSD (DoP)), a Rega Brio-R amp, and Harbeth P3ESR speakers. And a Wharfedale sub.I have awared 4 stars mainly because the unit isn't exactly attractive, but in terms of sound I think all versions deserve 5 stars.

Do not buy this if you have a recently upgraded Mac.It doesn't work with Sierra or High Sierra. LH Labs doesn't answer support requests.

I ordered the Geek Pulse DAC which this listing states that it has balanced XLR outputs but this is false, when I opened the box it only has RCA outputs. It clearly states on this page that all 3 models have XLR outputs, please fix this.

The product stopped working after a very moderate use and customer support is unresponsive.It's been 4 months since my amp stopped working and so far I was not able to get ANY attention from their customer support. The only thing they say is that their tech support is very shorthanded and understaffed. So if you buy this item, you will not get ANY support.

Pros:Plays every format of music I tried it with.Easy to install driver with Windows. Works with my Android devices as well.All aspects of the sound are excellent. Dead quiet, excellent sound stage, good output, etcWell made, runs cool, looks good, 3 output ranges and simple but complete controls.Manual available online if needed. Excellent support and forums.Cons:Not enough gain/output for my HiFiMan HE-560 and HD800 headphones.Overpriced for 2016. Equal quality units less expensive now.Thoughts:Wish it had an analog input for use as just an amp.Wish the IR remote codes were available so it would work with my universal remote. Does work with an Apple remote.Replace the knob with a larger one if not using an IR remote. Much nicer feel and control.Format compatibility not important TO ME since I convert all to 44.1/16 bit FLAC anyway since anything more is a waste for playback.Higher res is only useful for listening before converting, recording or editing.At least read the first article below before flaming me. I won't argue if you think differently. I used to.https://xiph.org/~xiphmont/demo/neil-young.htmlhttp://www.bostonaudiosociety.org/bas_speaker/abx_testing2.htmhttp://www.audiocheck.net/blindtests_16vs8bit.phphttp://www.aes.org/e-lib/browse.cfm?elib=14195

Wow what a difference from just the sound from the output jack on a laptop. I have owned this unit for about 8 months and I am wholly sold. Stunning soundscape and a perfect balance for my Sennheiser HD 598s.