Geek Pulse: Geek desktop DAC/AMP by Light Harmonics
Apr 5, 2014 at 4:38 AM Post #1,486 of 13,800
I just checked my e-mail and this was in the inbox:
Things are picking up steam here at LH Labs. While we've had one team focused on delivering Geek Outs to our backers, we have another preparing to launch an Indiegogo campaign, and another compiling all the data from our listening tests to finalize the Geek Pulse family. I have some fun news in this regard.

First, we've decided to include a couple of new inputs. For Geek Pulse and Geek Pulse S, there will be an AES/EBU digital input included that we hadn't planned on before. For Geek Pulse X, there will be an additional S/PDIF input that wasn't included in the initial design. By doing this, there's greater flexibility for all of our backers and future consumers, and it helps us to standardize the BOM's across the product line, making it less expensive to make chassis components, and easier to train our assembly staff. It's a win-win!

Second, after more listening tests, we've decided that we'll utilize a minimum phase digital filter in all the Geek Pulse DACs. It still needs to be fine-tuned, but our initial impressions are that using this filter minimizes an unnatural pre-ring that we've detected. We want to make Geek Pulse comparable to ANY DAC in the < $5,000 range. Our listening tests are done in direct comparison to our Sire DAC, which is our gold standard. We also compare it to other DAC's we've collected that we esteem to be overachievers. We think by holding Geek Pulse up against such stiff competition, everybody will be happy.

Lastly, we’ve discovered a campaign logic flaw. During the campaign, we used ab S/PDIF output as a stretch goal. Then, near the end of the campaign, we were asked to include femto clocks inside inside Geek Pulse to imporove jitter performance. We've found that these two goals are technically contradicting to one another. By adding an S/PDIF output (not an input), we need to insert one more layer of logic inside the digital audio signal chain. And has decreased the jitter performance, undoing the improvement the femto clocks added. Therefore, we've decided to cancel this feature and want to replace it with another one.

We don't take this lightly. Larry has been in constant communication with the Geek Force about the issue and, after a lot of input, came to this decision. What was presented to us by the Force as an alternative is adding one of the following options:

User-selectable filters
Mu Metal clock shields
Improved connectors
Silver gain relay array

What do you think? Please visit Geek Force to cast your vote.

Thank you!

Gavin

My vote goes for the user-selectable filter. I would be interested in comparing filters as only the Cambridge Audio DacMagic can do that as far as I know. I can't tell a difference between the linear and minimum phase filters with software under an ABX test.


Or maybe improved connectors would be a better choice in the long run for product durability.
http://hifiduino.blogspot.com/2009/05/wm8741-digital-filters.html
I can hear some differences if I focus on specific instruments. I've compared filter 5 with filter 1 and at the time, filter 1 had a bit more "reverb" or "echo". Filter 1 and 3 was hard to tell apart. If I listen to the performance of the music as a whole, I couldn't tell the difference between the filters. However, it would require a lot of patience to listen to these filters. Stereophile did some experiments on these type of filters and published some results. Search for "apodizing" or "minimum phase" in Stereophile


http://www.stereophile.com/content/ringing-false-digital-audios-ubiquitous-filter-filter-listening-impressions
http://www.stereophile.com/digitalprocessors/cambridge_audio_azur_dacmagic_da_converter/index.html


It seems to me that these filters have very minimal impact in the sound quality, in which case I probably wouldn't bother with them after the first month of playing with them, and having better connecters would have been a better choice.
 
Apr 5, 2014 at 4:42 AM Post #1,487 of 13,800
thanks for the update...heck, i have no clue which option i'd prefer. i was thinking that removing the SPDIF out was already a feature in itself and happy about that decision. anything else is, as they say, gravy.
 
p.s. i'm really really excited about the potentially awesome DAC capabilities of this thing... "<$5000 range?" geez, i'll take that range any day.
 
Apr 5, 2014 at 4:00 PM Post #1,489 of 13,800
  So the Pulse is compared to a $120,000 Sire DAC.  Cool...


They're using the Sire as a reference to see how the Pulse compares to it.  They're not saying that the Pulse will be as good as the Sire.
 
Apr 5, 2014 at 4:34 PM Post #1,491 of 13,800
 
They're using the Sire as a reference to see how the Pulse compares to it.  They're not saying that the Pulse will be as good as the Sire.


Hmmm.  I thought that what it said... "compared"
confused_face_2.gif
.  Anyway, the fact that it is "compared" against the Sire is interesting enough.  But...
 
...who have heard the Sire?  I don't think it is available yet except perhaps to Bill Gates?
 
Apr 5, 2014 at 6:13 PM Post #1,492 of 13,800
  thanks for the update...heck, i have no clue which option i'd prefer. i was thinking that removing the SPDIF out was already a feature in itself and happy about that decision. anything else is, as they say, gravy.
 
p.s. i'm really really excited about the potentially awesome DAC capabilities of this thing... "<$5000 range?" geez, i'll take that range any day.


I've seen Larry mention he was shooting for the 3K-5K price range before. Honestly, I thought it was very likable and a little funny that he takes so much pride in his own product. After hearing the GeekOut, I can see he is not being funny at all. It is pretty stunning and my expectations for the Pulse just went up 10 fold. Things got a lot more exciting all the sudden.
 
Apr 5, 2014 at 6:23 PM Post #1,493 of 13,800
 
I've seen Larry mention he was shooting for the 3K-5K price range before. Honestly, I thought it was very likable and a little funny that he takes so much pride in his own product. After hearing the GeekOut, I can see he is not being funny at all. It is pretty stunning and my expectations for the Pulse just went up 10 fold. Things got a lot more exciting all the sudden.

i've been looking at $1000 DACs and haven't bit on any yet. ideally, i'd want something like the Auralic VEGA, but it's more than i want to spend...if the pulse x can get near the VEGA, i'd be really impressed.
 
Apr 5, 2014 at 6:26 PM Post #1,494 of 13,800
  i've been looking at $1000 DACs and haven't bit on any yet. ideally, i'd want something like the Auralic VEGA, but it's more than i want to spend...if the pulse x can get near the VEGA, i'd be really impressed.

Ask me a week ago and I would have said probably not...those are really big shoes to fill. Now, I think it's going to be close. 
Hold on to your cash until some Pulse reports start coming in..I think it will be worth it.

There is some Larry Ho magic going on with the GeekOut. Meaning, something different is going on and I can't quite get my finger on it. Reviews of the high-end LH cable are a bit similar to my impression/confusion. It is massively detailed and yet somehow still smooth and not aggressive for all that info it is pulling up. 

Add dual-mono for the Pulse X over the GO, LPS instead of USB power and on and on...I am excited :D
 
Apr 6, 2014 at 3:06 AM Post #1,495 of 13,800
Update from Larry!
 
  1. Larry Ho
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But I think Geek Force worth to make it happen.

In Geek Pulse key analog stage supply part, I decide to add 4 Elna RFS II Capacitors there. It provides the final silky touch and the magic sound I want. It will increase the cost quite a bit. But I think for the Geek Pulse and Geek Force. You worth it.

FYI, this Elan RFS II Silmik cap usually be put in the devices more than $10K, Da Vinci use it. 
cool.png


That is Larry's little update for today... Saturday Night.

Good Weekend!

 
Apr 6, 2014 at 6:40 AM Post #1,496 of 13,800
Nice!  Hehe the sound is literally silky
 
Elna Silmic (ROS Series) & Silmic II (RFS Series) Electrolytic Capacitors

High-grade Silk fiber capacitors for Audio.
The SILMIC series are Elna's highest grade audio capacitors that exhibit superior acoustic characteristics. An entirely new type of electrolytic separating paper is used, containing silk fibers. The extreme softness of silk can mitigate vibrational energy (generated by the electrodes, by external vibrations and by electromagnetic fields). Due to it's new electrolytic and foil design the signal propagation speed has increased (the ESR is reduced) and a more powerful, yet-mellow, sound is possible than before. When these capacitors were subjected to aural evaluations, the high range peak and midrange roughness were reduced substantially. Also, the low range richness and power were increased in the obtained high-quality sound.
 
Apr 6, 2014 at 10:25 AM Post #1,497 of 13,800
  Update from Larry!
 
  1. Larry Ho
  2. Moderator
  3. Moderator-icon.png
  4. OFFLINE
  5. Karma: 38  
But I think Geek Force worth to make it happen.

In Geek Pulse key analog stage supply part, I decide to add 4 Elna RFS II Capacitors there. It provides the final silky touch and the magic sound I want. It will increase the cost quite a bit. But I think for the Geek Pulse and Geek Force. You worth it.

FYI, this Elan RFS II Silmik cap usually be put in the devices more than $10K, Da Vinci use it. 
cool.png


That is Larry's little update for today... Saturday Night.

Good Weekend!



Thanks go out to Larry!
 
Apr 6, 2014 at 7:39 PM Post #1,498 of 13,800
Interesting. How much were the capacitors before this decision was made? Mouser has those capacitors at $0.30-1.30 a piece if not purchased in bulk. Capacitors are usually at around this price, no?
http://www.mouser.com/search/refine.aspx?Ntk=P_MarCom&Ntt=165227470


[rule]Also interesting is that the JDS Labs C5D I have can have a normal FIR filter or a low-latency (read: minimum phase filter) configured via Arduino programming interface. On default it's set to high, or the minimum phase filter. I e-mailed them and they said that they couldn't hear a difference between the filter being on high or low.
http://www.ti.com/lit/gpn/pcm5102a
^ go to page 15

Yet more evidence that the filter type doesn't make a whole lot of difference in the sound quality...
 
Apr 6, 2014 at 11:40 PM Post #1,499 of 13,800
Interesting. How much were the capacitors before this decision was made? Mouser has those capacitors at $0.30-1.30 a piece if not purchased in bulk. Capacitors are usually at around this price, no?
http://www.mouser.com/search/refine.aspx?Ntk=P_MarCom&Ntt=165227470
 
Also interesting is that the JDS Labs C5D I have can have a normal FIR filter or a low-latency (read: minimum phase filter) configured via Arduino programming interface. On default it's set to high, or the minimum phase filter. I e-mailed them and they said that they couldn't hear a difference between the filter being on high or low.
http://www.ti.com/lit/gpn/pcm5102a
^ go to page 15

Yet more evidence that the filter type doesn't make a whole lot of difference in the sound quality...

Hi, there
 
Don't just grab the direct cost from mouser. That is through hole caps, you need skill people hand solder these caps there and manually tested each solder points.
:wink:
 
PCM5102 is just like ESS9023.... Well they are direct-voltage-output DAC ICs. Cheaper to make, easier to implement for normal designer, but since it combined so much analog stage INSIDE a single IC, I doubt the digital filter difference will reveal.... 
 
Cheers,
Larry
 
Apr 7, 2014 at 1:30 AM Post #1,500 of 13,800
  Hi, there
 
Don't just grab the direct cost from mouser. That is through hole caps, you need skill people hand solder these caps there and manually tested each solder points.
:wink:
 
PCM5102 is just like ESS9023.... Well they are direct-voltage-output DAC ICs. Cheaper to make, easier to implement for normal designer, but since it combined so much analog stage INSIDE a single IC, I doubt the digital filter difference will reveal.... 
 
Cheers,
Larry

But these skilled people were already soldering/testing each solder point with cheaper capacitors...
 

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