Aug 21, 2013 at 9:20 AM Thread Starter Post #1 of 17

geneticwarrior

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Hi all,
I was wondering about this DAC/AMP, it looked perfect for me as I typically do all my listening (to anything).  Can anyone with more knowledge on amps and DACS tell me how you think this might work for a headset that needs a decent amp? I was really wanting to buy a nice set of phones for trance/dance/electronic music, as well as games (more interested in music fidelity). I have read a bit and I keep coming up with BT990 or other BeyerDynamic, or Sennheiser 650s, as well as a few others that like AKG and Audio-Thecnica models.  I'd love some more input as to what ya'll think might go best with this DAC/AMP. I have already backed it so that's the DAC/AMP I will be using, not looking to get another/different amp/DAC. Thanks in advance for any responses!  The DAC/AMP on kickstarter is called the Geek i believe. just do a search for geek in the technology section.
 
Aug 21, 2013 at 8:32 PM Post #2 of 17
Hi Geneticwarrior, I was searching for post about the GEEK here in head-fi and (kinda surprise to see) no one is talking about it yet until I saw your posting.
 
Yes, the Kickstarter project you mentioned is called GEEK: A New USB Awesomifier for Headphones (http://www.kickstarter.com/projects/gavn8r/geek-a-new-usb-awesomifier-for-headphones). I am one of the backers too. ;). It's basically a hi-fidelity replacement/amplifier for your onboard sound card. The company behind this wonderful project is Light Harmonic, the same company that manufactures the $20,000 Da Vinci DAC. Although the GEEK is much smaller project but I have faith in them (fingers crossed).
 
Since the project is pretty much still in design and pre-manufacturing phase, I guess very few have tested it. However, there are some specs of the GEEK at Gavin's (the project starter) blog - http://mustgeekout.blogspot.com/2013/08/geek-vs-others.html. Power wise, it is stated as 450mW@30Ω. For comparison, Audioquest Dragonfly has 125mW@32Ω and Meridian Explorer has 130mW@16Ω and the FiiO E17 I'm currently using has > 220 mW@32Ω /> 290 mW@16Ω. I do not own the headphones you mentioned, but by looking at the numbers, I guess it should be able to drive most headphones adequately. If you feel that it still not enough power, you can always get another more powerful amp and connect it to the line out of the GEEK.
 
Aug 21, 2013 at 9:12 PM Post #3 of 17
their project video @2:53, watch the guy put on the hd800 on... backwards... /facepalm.
 
anyway i am extremely skeptical about this project (not whether they'll deliver their product, but whether the product is actually good). they use a lot of marketing buzzwords and the product seems to be targeted at non-audiophiles (e.g. emphasis on importance of bass, beats executive shown etc), so i'm not sure how good it will actually sound. looks like they are trying to cram a ton of features onto it to win the feature chart war (again, to look good to the average consumer), but most of it is kinda useless, especially in a mobile, portable setting (e.g. DSD, 384khz sample rate, rly?!).
 
also the power output seems pretty high especially considering the 0.01% thd. the other usb powered devices only draw around 120mW because usb itself does not provide that much power (the fiio e17 and many other portal amps have a battery for this exact reason, so they can output more power). usb specs for data connectors tops out at 500mA, which is 2.5W, but typically draws around 100mW (especially on a laptop), so that's around 500mW for typical use. how they are able to output 90% of that to headphones (with minimal distortion) is beyond me, but who knows maybe they figured out a way.
 
anyway just some of my skepticism. we'll wait and see how it turns out i guess.
 
Aug 21, 2013 at 10:16 PM Post #4 of 17
Quote:
their project video @2:53, watch the guy put on the hd800 on... backwards... /facepalm.
 
anyway i am extremely skeptical about this project (not whether they'll deliver their product, but whether the product is actually good). they use a lot of marketing buzzwords and the product seems to be targeted at non-audiophiles (e.g. emphasis on importance of bass, beats executive shown etc), so i'm not sure how good it will actually sound. looks like they are trying to cram a ton of features onto it to win the feature chart war (again, to look good to the average consumer), but most of it is kinda useless, especially in a mobile, portable setting (e.g. DSD, 384khz sample rate, rly?!).
 
also the power output seems pretty high especially considering the 0.01% thd. the other usb powered devices only draw around 120mW because usb itself does not provide that much power (the fiio e17 and many other portal amps have a battery for this exact reason, so they can output more power). usb specs for data connectors tops out at 500mA, which is 2.5W, but typically draws around 100mW (especially on a laptop), so that's around 500mW for typical use. how they are able to output 90% of that to headphones (with minimal distortion) is beyond me, but who knows maybe they figured out a way.
 
anyway just some of my skepticism. we'll wait and see how it turns out i guess.

 
Hi Jd007the GEEK is using TI PCM1795 DAC chip which is being used by many great DAC out there. One of them is TEAC UD-501, which does DSD 5.6MHz and PCM 384kHz too. Currently the usage of the GEEK DAC/Amp is focused mainly for computer environment (eg. laptop/desktop), which make sense for the high bit and sample rate. Although there are many request to make it work for mobile devices like smartphones and tablets, but I guess that will be another product or project.
 
I'm not quite sure about power output calculation for the amp section, but there are other USB DACs out there have high output power too. One of them is CEntrance DACport (http://centrance.com/products/dacport/) with total output power of 1.5W. Well, I guess there are many geniuses out there. :P
 
If you want to know more you can always drop a message to Gavin Fish (http://www.kickstarter.com/profile/gavn8r), the creator of the project.
 
Aug 21, 2013 at 10:27 PM Post #6 of 17
Quote:
I would love to know more about the geek specs wise.  I have no idea what chip it uses or how much power it puts out. It reminds me of my Audio quest dragonfly (usb dac/amp uses a saber dac and gives a ok amount of power).  By the way what is your price range for headphones and amp/dac?  And as a side note if your going to get a pair of headphones with 300ohms or 600ohms then you need a amp powerful enough to power them.  I believe the geek was intended to give out more power to less then 32ohms headphones (which is what normal people use).

Hi David, I have posted a link to the comparison between the GEEK and other USB DAC in my previous thread. In case you missed it, here's the link again http://mustgeekout.blogspot.com/2013/08/geek-vs-others.html. You can take a look at the specs there.
 
Apparently Larry Ho, one of the designers of the GEEK is posting replies in another thread (http://www.head-fi.org/t/677263/light-harmonic-geek) I'm sorry to the thread starter. It's not my intention to divert people away from your thread, but just trying to let you guys know the designer is in the house. :P
 
Aug 21, 2013 at 10:41 PM Post #7 of 17
Quote:
Hi David, I have posted a link to the comparison between the GEEK and other USB DAC in my previous thread. In case you missed it, here's the link again http://mustgeekout.blogspot.com/2013/08/geek-vs-others.html. You can take a look at the specs there.
 
Apparently Larry Ho, one of the designers of the GEEK is posting replies in another thread (http://www.head-fi.org/t/677263/light-harmonic-geek) I'm sorry to the thread starter. It's not my intention to divert people away from your thread, but just trying to let you guys know the designer is in the house. :P


Thanks wow the amp is very impressive actually Class A and able to put out 450mW into 32ohm headphones (4ohms output impedance isn't great but shouldn't be a deal breaker for the price).  Asynchronous usb 2.0 is nice.  The dac chip is also great.
 
Aug 21, 2013 at 10:46 PM Post #8 of 17
Quote:
 
Hi Jd007the GEEK is using TI PCM1795 DAC chip which is being used by many great DAC out there. One of them is TEAC UD-501, which does DSD 5.6MHz and PCM 384kHz too. Currently the usage of the GEEK DAC/Amp is focused mainly for computer environment (eg. laptop/desktop), which make sense for the high bit and sample rate. Although there are many request to make it work for mobile devices like smartphones and tablets, but I guess that will be another product or project.
 
I'm not quite sure about power output calculation for the amp section, but there are other USB DACs out there have high output power too. One of them is CEntrance DACport (http://centrance.com/products/dacport/) with total output power of 1.5W. Well, I guess there are many geniuses out there. :P
 
If you want to know more you can always drop a message to Gavin Fish (http://www.kickstarter.com/profile/gavn8r), the creator of the project.

The DAC chip used is actually not the most important part of a DAC, nor the hardest to implement. DAC makers do not make DAC chips themselves, and they usually choose from a few well known manufacturers (e.g. TI, Wolfson), and since DAC chips are cheap, even budget DACs can (and often do) use good DAC chips. What really differentiates a good DAC from a mediocre/bad one is the analog section after the DAC, because the analog signal the DAC chip outputs is quite weak, which needs to be amplified to line level for output. Of course, oversampling, precision anti-jitter clocks also affect the quality of the DAC, but not to the extent that the analog amplification stage does.
 
The DACport power output is actually kind of confusing IMO. It does not say at what load level it outputs 1.5W, but it does say that it has a 4.4V peak output swing, which is 8.8V peak to peak. High impedance phones need more voltage swings to drive properly, so this figure is probably for a high impedance load (300-600 ohm). If this voltage is applied to a 600Ohm load, the power output is actually only 129mW (power^2 = impedance * voltage). Even if it delivers 8.8V into 300Ohm, the power output is still just 258mW. anyway maybe i got the math all wrong. it is definitely possible to draw 1.5W from a USB, in fact the max for a normal usb port, taken from the specs, is 500mA, which at 5V is 2.5W. i doubt a laptop's USB has this much power though, which is why I originally used 100mA for the 500mW figure.
 
Aug 22, 2013 at 2:58 AM Post #9 of 17
For those who were wondering, I'm eyeballing the Sennheiser HD 650 pretty hard. Think I would need a better amp to connect to the Geek for best results on this headphone set? Thanks for all the replies! Very useful information, I am a noob with audio terminology.
 
Aug 29, 2013 at 11:39 AM Post #12 of 17
Thought I should share with you guys Gavin's latest update on GEEK

Biggest news in my view is the Output impedance of .47 ohms...

"http://www.youtube.com/watch?v=scbrcrojq78
Video Highlights:

Geek's output impedance is officially set to 0.47 Ohm. - Must Geek Out: GEEK vs. the Others
2L Records offers Geek Backers discount off any or all titles available in their catalog. - Must Geek Out: Record Label 2L offers Geek Backers Discount on High Resolution Audio Downloads
"

PS: I'm not affiliated with Light Harmonics in any way (but hey feel free to drop a Da Vinci dual dac for the advertising... I do need a new dac for my system 
color]
 )
 
Aug 29, 2013 at 11:48 AM Post #14 of 17
Gavin's comment on kickstarter:
 
 
"
 
"Low" impedance headphones/earphones— < 60 Ω: I suggest Geek (450 mW @ 16 Ω) 
"Mid" impedance headphones/earphones— 60 Ω to 299 Ω: I suggest Super Geek (720 mW @ 16 Ω) 
"High" impedance headphones/earphones— 300 Ω and above: I suggest Super-Duper Geek (1000 mW @ 16 Ω)
 
"
 

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