Geek Pulse: Geek desktop DAC/AMP by Light Harmonics
Dec 1, 2014 at 1:27 AM Post #3,091 of 13,800
   
I am still looking for *any* evidence that a digital cable affects sound.  And by "any evidence" I mean either:
 
1.  An explanation that my poor brain can understand.
 
2.  A trial that my poor ears can listen any difference.
 
So far, alas, I have not found any.  If people have (1), please share.  As of (2), I'll keep looking in head-fi meetings.  And, of course, I'll receive a 1G cable when my pulse eventually arrives.  I'll try an A/B against a cheap USB cable.

 
+1
The only 'expensive' USB cables I have ever tried, costing only in the range of $75, and I couldn't hear any difference with sub $10 cables (using pretty good gears, HD800, T1, etc). But I'm open and really eager to find the truth or to hear any difference between sub $10 good quality USB and those > $100 USB cables.  I know SPDIF coaxial cable might have problem with reflection, thus there might be differences between cables. But for USB, I don't see any good explanation so far. Probably good conductor for the power section might cause a different, but that would apply only for DACs requiring power from USB port.
 
Dec 1, 2014 at 2:00 AM Post #3,092 of 13,800
Yeah I've inquired why bandwidth would have anything to do with the sound quality.

Say we have a DSD128 track playing on the Geek Out or Pulse.
44.1 kHz * 1000 Hz/kHz * 128 times the sampling rate of CD * 1-bit audio * 2 channels = 11289600 bit/s = 11.2896 Mbps

A standard USB 2.0 cable should have more than enough bandwidth for this type of music so why does Light Harmonic insist on creating a USB cable that has 4 times the bandwidth of USB 2.0 specifications (480 Mbit/s for high-speed applications)?

And I thought USB interfaces use some sort of checksum-like process for verification of accurate data.
 
Dec 1, 2014 at 3:57 AM Post #3,093 of 13,800
Yeah I've inquired why bandwidth would have anything to do with the sound quality.

Say we have a DSD128 track playing on the Geek Out or Pulse.
44.1 kHz * 1000 Hz/kHz * 128 times the sampling rate of CD * 1-bit audio * 2 channels = 11289600 bit/s = 11.2896 Mbps

A standard USB 2.0 cable should have more than enough bandwidth for this type of music so why does Light Harmonic insist on creating a USB cable that has 4 times the bandwidth of USB 2.0 specifications (480 Mbit/s for high-speed applications)?

And I thought USB interfaces use some sort of checksum-like process for verification of accurate data.


No,isochronous doesn't have any check-sum or packet resend functionality - the goal with this is to have timely data rather than total data integrity. How many data errors really occur in most cases I'm not sure, but Larry said he likes to keep very tight impedance tolerances as well(2%?).
 
Dec 1, 2014 at 6:52 AM Post #3,094 of 13,800

Besides, what other item can you have made for $10 and charge north of $500 for?
 
Dec 1, 2014 at 8:38 AM Post #3,095 of 13,800
  I lost track when they added the Fi to the X....LOL!!

lol, i barely know what i actually have ! 
i have to look from time to time
 
Dec 1, 2014 at 8:39 AM Post #3,096 of 13,800
  "If you dont get a USB cable of this / similar quality why are you spending money of a high end DAC???"
 
-- or --
 
Not getting these cables or similar high end cables will create a noticeable noise and create a weak point in a Geek Pulse X + LPS4 + HE 560 system
 
If either holds true then I'll get em. If a monster USB cable works i'll put out a WTB on my local forum to save exchange rates / post. (Australia here)

 
I've hear this argument quite a few times with regards to USB cables in this thread (and/or at LHLabs?). But in my mind shouldn't the 3L buffer, asynch transmission, LPS4 and any other pixie dust sprinkled in the circuit make the Pulse LESS sensitive to USB cables? That is, assuming there is any noise or distortion that we can actually hear/perceive in the first place - oh boy, here we go on the cable debates 
very_evil_smiley.gif

 
Dec 1, 2014 at 8:45 AM Post #3,097 of 13,800
   
I am still looking for *any* evidence that a digital cable affects sound.  And by "any evidence" I mean either:
 
1.  An explanation that my poor brain can understand.
 
2.  A trial that my poor ears can listen any difference.
 
So far, alas, I have not found any.  If people have (1), please share.  As of (2), I'll keep looking in head-fi meetings.  And, of course, I'll receive a 1G cable when my pulse eventually arrives.  I'll try an A/B against a cheap USB cable.

i was somewhat skeptical about cables in general, i figured i'd just make sure any cables (usb included) were of good quality 
i started with audioquest forest, and then tried a audioquest carbon, no real difference that i could hear.
i happened upon a good deal on a nordost blue heaven usb cable, i heard a definite improvement , not night and day, but a more open sound. 
now i wouldn't "bet my "paycheck" on that, but i kept the cable ! just my experience , as they say, YMMV 
 
Dec 1, 2014 at 8:47 AM Post #3,098 of 13,800
 
No,isochronous doesn't have any check-sum or packet resend functionality - the goal with this is to have timely data rather than total data integrity. How many data errors really occur in most cases I'm not sure, but Larry said he likes to keep very tight impedance tolerances as well(2%?).

 
Yes, but the Pulse uses asynchronous USB transmission in which the data packets are checked.
 
Dec 1, 2014 at 9:00 AM Post #3,099 of 13,800
  It'll still sound great, again just not as nice as the other options that require additional funds.

 
In theory... or as the marketers would have you believe. 
wink.gif

 
As of yet, I do not know of any actual customer impressions, reviews, comparisons, blind testing, etc. I'm not one to discount the difference cables and other measures can make, I even have a Quantum Symphony plugged into my system which can seem like borderline snake oil. But we need to some actual experiences (which there should be since Pulses have shipped, yes?).
 
Dec 1, 2014 at 9:41 AM Post #3,100 of 13,800
Dec 1, 2014 at 10:16 AM Post #3,101 of 13,800
 
Yeah I've inquired why bandwidth would have anything to do with the sound quality.

Say we have a DSD128 track playing on the Geek Out or Pulse.
44.1 kHz * 1000 Hz/kHz * 128 times the sampling rate of CD * 1-bit audio * 2 channels = 11289600 bit/s = 11.2896 Mbps

A standard USB 2.0 cable should have more than enough bandwidth for this type of music so why does Light Harmonic insist on creating a USB cable that has 4 times the bandwidth of USB 2.0 specifications (480 Mbit/s for high-speed applications)?

And I thought USB interfaces use some sort of checksum-like process for verification of accurate data.


No,isochronous doesn't have any check-sum or packet resend functionality - the goal with this is to have timely data rather than total data integrity. How many data errors really occur in most cases I'm not sure, but Larry said he likes to keep very tight impedance tolerances as well(2%?).


But Pulse is asynchronous, right?
 
Dec 1, 2014 at 12:47 PM Post #3,103 of 13,800
 
In theory... or as the marketers would have you believe. 
wink.gif

 
As of yet, I do not know of any actual customer impressions, reviews, comparisons, blind testing, etc. I'm not one to discount the difference cables and other measures can make, I even have a Quantum Symphony plugged into my system which can seem like borderline snake oil. But we need to some actual experiences (which there should be since Pulses have shipped, yes?).

 
I have the GO SE and it spanks the GO 1000 that I had before. Considering that the SE contains several things that my Pulse Xfi will have (for example femto clocks and upgraded active components) I have no doubt that the Pulse will sound excellent.
 
Dec 1, 2014 at 12:54 PM Post #3,104 of 13,800
   
I have the GO SE and it spanks the GO 1000 that I had before. Considering that the SE contains several things that my Pulse Xfi will have (for example femto clocks and upgraded active components) I have no doubt that the Pulse will sound excellent.

i missed this, you have received a pulse ??
 
Dec 1, 2014 at 12:55 PM Post #3,105 of 13,800
   
I have the GO SE and it spanks the GO 1000 that I had before. Considering that the SE contains several things that my Pulse Xfi will have (for example femto clocks and upgraded active components) I have no doubt that the Pulse will sound excellent.

 
Sorry... I misread your original post. When you said "other options that require additional funds" I thought that you were referring to the USB cables.
 

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