Hearing the Difference: Synchronous vs Asynchronous

[justex07]

I recently picked up two FiiO DAC/Amps while I waited for my Fostex x Massdrop TH-X00 + JDS Labs Element purchases hopefully arriving around May (waiting to order the Element until the Fostex is on the way, unless you have another recommendation!).
 
The two FiiO devices in question are the FiiO K1 and FiiO E10K Olympus.
 
FiiO K1 = $40

1. Savitech SA9023A USB Audio Streaming Controller
2. Texas Instruments PCM5102 DAC
3. TPA61332A Amp

 
FiiO E10K Olympus = $125 then $100 then $75 then $65

1. GFec TE7022L USB Audio Streaming Controller
2. Texas Instruments PCM5102 DAC
3. LMH6643 Amp

 
Listening to each of these via Audio Technica ATH-M50, Sennheiser HD600, Grado SR80i, Philips Fidelio X2 and V-Moda Crossfade M100 headphones, every single time I preferred the sound of the FiiO K1 to the FiiO E10K (with the exception of the Sennheiser where volume didn't quite make it where I wanted it). 
 
It's really hard for me to pinpoint what it is about the K1 that bests the (much more powerful) E10K except that the K1 seems more precise, proactive instead of reactive and fast. It doesn't seem to be at risk of complicated bass complicating midrange and treble. 

 
N.B. This is with Bass Boost off on the E10K (the bass boost is pretty awful IMHO)
 
Looking at the chips it would seem it can't be the DAC causing this as they share the same DAC. At first I thought maybe it was the different amp chips in each but when I connected the K1 and E10K (via its line out) to a Sonic Adventure Reality amp I still preferred the K1, even in a blind test flipping the input selector on the amp.
 
[Obviously the amp chip could still be at issue here since I can't bypass the TPA61332A on the K1 which is partly the point of this post]
 
Knowing all this, do you think that I am actually hearing the difference of the USB Audio Streaming Controller? The K1 using an asynchronous Savitech while the E10K using the older synchronous GFec TE7022L. I've read a few articles about the differences between the two technologies and generally speaking async is the way to go I just find it hard to believe something this tiny could make such a difference. Or can it?
 
Finally... perhaps this is why FiiO quietly discontinued (?) the E10K shortly after the K1 was released? Most (all?) online stores that carry FiiO products (from Amazon to B&H to even Massdrop) sharply discounted the FiiO E10K until all stock was exhausted. Maybe this is a sign that a new E10K is on the way with asynchonous USB. Only time will tell. Luckily we apparently only have to wait until either March 16 or April 10th to find out. That's when retailers seem to expect their next shipments.
 
Curious as to your thoughts on this!
 

1.  Do you think it's possible to hear the difference between asynchronous and synchronous USB?
2. Have you experienced something like this before?
3. Do you think the price and stock fluctuations mean a new FiiO E10K on the horizon?
4. Any other thoughts are welcome, including the pairing of a JDS Labs Element to the Fostex TH-x00 
   

 
Thanks!

 

[justex07]

I feel like I should add that the differences I hear are super nuanced but I do find myself spending way more time with the FiiO K1 vs the E10K which is why this interests me so much.
 
You'd think I would lean towards the more powerful E10K even it's just to use the Line out to the Sonic Adventure Reality (which is an OK amp, to be honest I'm looking forward to replacing it with something like the Element) vs the K1 to the Sonic Adventure Reality.

 

[fjrabon]

  I recently picked up two FiiO DAC/Amps while I waited for my Fostex x Massdrop TH-X00 + JDS Labs Element purchases hopefully arriving around May (waiting to order the Element until the Fostex is on the way, unless you have another recommendation!).
 
The two FiiO devices in question are the FiiO K1 and FiiO E10K Olympus.
 
FiiO K1 = $40

1. Savitech SA9023A USB Audio Streaming Controller
2. Texas Instruments PCM5102 DAC
3. TPA61332A Amp

 
FiiO E10K Olympus = $125 then $100 then $75 then $65

1. GFec TE7022L USB Audio Streaming Controller
2. Texas Instruments PCM5102 DAC
3. LMH6643 Amp

 
Listening to each of these via Audio Technica ATH-M50, Sennheiser HD600, Grado SR80i, Philips Fidelio X2 and V-Moda Crossfade M100 headphones, every single time I preferred the sound of the FiiO K1 to the FiiO E10K (with the exception of the Sennheiser where volume didn't quite make it where I wanted it). 
 
It's really hard for me to pinpoint what it is about the K1 that bests the (much more powerful) E10K except that the K1 seems more precise, proactive instead of reactive and fast. It doesn't seem to be at risk of complicated bass complicating midrange and treble. 

 
N.B. This is with Bass Boost off on the E10K (the bass boost is pretty awful IMHO)
 
Looking at the chips it would seem it can't be the DAC causing this as they share the same DAC. At first I thought maybe it was the different amp chips in each but when I connected the K1 and E10K (via its line out) to a Sonic Adventure Reality amp I still preferred the K1, even in a blind test flipping the input selector on the amp.
 
[Obviously the amp chip could still be at issue here since I can't bypass the TPA61332A on the K1 which is partly the point of this post]
 
Knowing all this, do you think that I am actually hearing the difference of the USB Audio Streaming Controller? The K1 using an asynchronous Savitech while the E10K using the older synchronous GFec TE7022L. I've read a few articles about the differences between the two technologies and generally speaking async is the way to go I just find it hard to believe something this tiny could make such a difference. Or can it?
 
Finally... perhaps this is why FiiO quietly discontinued (?) the E10K shortly after the K1 was released? Most (all?) online stores that carry FiiO products (from Amazon to B&H to even Massdrop) sharply discounted the FiiO E10K until all stock was exhausted. Maybe this is a sign that a new E10K is on the way with asynchonous USB. Only time will tell. Luckily we apparently only have to wait until either March 16 or April 10th to find out. That's when retailers seem to expect their next shipments.
 
Curious as to your thoughts on this!
 

1.  Do you think it's possible to hear the difference between asynchronous and synchronous USB?
2. Have you experienced something like this before?
3. Do you think the price and stock fluctuations mean a new FiiO E10K on the horizon?
4. Any other thoughts are welcome, including the pairing of a JDS Labs Element to the Fostex TH-x00 
   

 
Thanks!

Really this depends a lot on your source.  Essentially Asynchronous USB takes control, and then doesn't depend on your computer's (potentially bad) clock.  If your computer's clock is doing an admirable enough job, then the difference is virtually impossible to tell.  If your computer's clock has issues, the difference can be incredibly obvious to even "regular" listeners.  And obviously it can be anywhere in between.  
 
For example, with my macbook pro, I have an old Hotaudio HOT USB1 that was synchronous, and it sounds fine.  But if I use it on my old work PC at my office, it sounds like complete trash, while my m9XX sounds just the same on both computers.  

 

[justex07]

 
Really this depends a lot on your source.  Essentially Asynchronous USB takes control, and then doesn't depend on your computer's (potentially bad) clock.  If your computer's clock is doing an admirable enough job, then the difference is virtually impossible to tell.  If your computer's clock has issues, the difference can be incredibly obvious to even "regular" listeners.  And obviously it can be anywhere in between.  
 
For example, with my macbook pro, I have an old Hotaudio HOT USB1 that was synchronous, and it sounds fine.  But if I use it on my old work PC at my office, it sounds like complete trash, while my m9XX sounds just the same on both computers.  

 
Sounds like I'm not alone then. I use the FiiO K1 mostly on my work laptop, HP Elitebook, which has an absolutely awful internal DAC. As an Apple guy I've been spoiled by the quality DACs and headphone jacks on their computers. My custom Dell video editing desktop and Elitebook laptop both have awful distortion and noise coming from the headphone outputs which makes the K1 absolutely essential. 
 
I haven't tested the E10K on my PCs, just my MacBook Pro through a USB hub. Maybe I should try directly connecting or using another hub and see if that has any improvement on the E10K's performance.