[willkayak4food]

Hello,
 
After trying a couple of inexpensive DAC/headphone amp combos, I decided I liked the sound of the HiFiMan EF2A, and wanted to make it my primary portable DAC/amp for the moment.  Unfortunately, it seems to be causing a very disturbing problem.  Now and then, the sound will either stop entirely, or  worse, a loud static will suddenly begin.
 
1) If the sound simply stops entirely, in order to restore any sound at all, I have to unplug the USB cable, reinsert it, then restart playback.  Until it happens again.
 
2) If the static thing happens (instead of silence), I can stop what's currently playing and restart it without unplugging the USB cable, but if I don't unplug/reinsert the USB cable, there will be some level of background static during resumed playback.
 
This doesn't happen when I'm playing music through the speakers (in this case, USB digital output to Schiit Bifrost DAC, then to amp), or with my other portable DAC/amp, an Audioengine D1.  Only seems to happen with the HiFiMan EF2A.  This is really unfortunate, because this was my preferred choice in terms of sound quality for the portable headphone kit.
 
I'm currently using Foobar 2000 for playback on Windows 7.  Just to be sure it wasn't Foobar, I tried it on WinAmp as well, and the same thing happened.  In any event, I'm not sure I have all the correct settings in either Foobar or Windows "Sound" (control panel), but this problem  does seem to happen only when using the EF2A.
 
Has anyone experienced this issue with this particular DAC/amp?  Any suggestions?
 
Thanks!

 

[mrarroyo]

I have had similar issues with other dac/usb cables and ended up swapping the cable to solve the problem. Can't explain it but I thought it was a poor connection at the USB cable end.

 

[jamieuk147]

Yer me too

 

[willkayak4food]

Quote:

I have had similar issues with other dac/usb cables and ended up swapping the cable to solve the problem. Can't explain it but I thought it was a poor connection at the USB cable end.

 
I think I've pretty much ruled out the cable, as using the very same cable with a different DAC/amp never results in the same problem.  Using a different cable, the same thing happens with the EF2A, and again, not with the other DAC/amp.  Likewise, I don't think it has anything to do with the computer's USB port either (not sure if I can rule out the USB port on the EF2A--it seems just as solid a connection as the others--but I'm not yet sure I can prove this one way or the other).  So far, all I can say for sure is that the problem only occurs when using the EF2A.
 
I've written to HiFiMan about this, so hopefully, they'll be able to offer some help.
 
Thanks!

 

[willkayak4food]

Quote:

Yer me too

 
Hmmm.  Care to expound?

 

[ClieOS]

Have you tried the EF2A on another PC just to rule out the problem is not on the PC or confirm it is an PC issue? Also, try using different USB port if you haven't done so, and uninstall / reinstall the USB DAC driver for EF2A. If you have another high power device (Harddisk, WiFi adapter, etc) connected next to EF2A, you might want to remove it as well.

 

[willkayak4food]

Quote:

Have you tried the EF2A on another PC just to rule out the problem is not on the PC or confirm it is an PC issue? Also, try using different USB port if you haven't done so, and uninstall / reinstall the USB DAC driver for EF2A. If you have another high power device (Harddisk, WiFi adapter, etc) connected next to EF2A, you might want to remove it as well.

 
Thanks for your ideas.  I don't have another PC here, but may take this DAC/amp to try on someone else's computer tomorrow.  Just a few minutes ago, I did uninstall, then reinstall the driver, so I'll listen for a while to see what happens (nothing disagreeable, I hope! ).  The only other thing I have plugged into one of the other two USB ports at the moment is the little transmitter for the wireless mouse (I hate laptop track pads, so unless I'm in a situation where the mouse is just too inconvenient, that transmitter is always in one of the USB ports).  I have for now unplugged the USB cable that powers the laptop cooling pad (often, but not always, it's plugged in as well).
 
For the moment, I'm using the same USB cable as I was yesterday (DH Labs Silver Sonic digital USB), for two reasons: (1) As I test various possibilities (like uninstall/reinstall driver), I only want to change one thing at a time, and (2) I use this very same cable with my Audioengine D1, and as I mentioned last night, this issue has has never happened with that DAC/amp (tested with the D1 again last night, and as usual, there were no issues).  If the cable is bad, shouldn't I expect it to misbehave while being used with other components as well? 
 
In any event, I really do hope this issue can be--will be--solved, as I really do like the sound of this DAC/amp (even before my supposedly better tubes arrive sometime later his week), and would like to continue using it.  I haven't yet heard anything from HiFiMan in response to the inquiry I sent last night.  I'll continue testing one thing at a time.  Who knows?  Perhaps the driver uninstall/reinstall did something good?  So far, so good (at least for the past 30 minutes or so).
 
Finally, just a couple more things I'm thinking about...
 
1) Laptop power settings?  I just now changed all the "plugged in" power reduction settings to "never" (so that nothing changes during music playback, hopefully).
 
2) Foobar 2000 and/or Windows 7 "Sound" settings...  Are there tried and true sets of options that I should be using for these?  Any advice here would be greatly appreciated.  If I need to dig deeply into these settings, please offer as much detail as possible. 
 
Thanks again!

 

[willkayak4food]

Quote:

I'll continue testing one thing at a time.  Who knows?  Perhaps the driver uninstall/reinstall did something good?  So far, so good (at least for the past 30 minutes or so).

 
Oops!  Spoke (wrote) too soon.  It just happened again (sudden silence - requiring removing/replacing USB connection--at computer end--to restore working sound.  
 
It may have just been a coincidence, but I noticed that just about at the moment of the unhappy event, my anti-virus was updating itself (and preparing for its little "pop-up" telling me how many files were just updated).  I wonder if I should just disable those updates while playing music?  Perhaps I'll try that now...
 
[10 seconds later] -- it just happened again!  This time with no anti-virus update in progress!  So, I guess it's not that.  This time, I unplugged the USB cable from the EF2A end.  Sound now restored.   Oh... and just now, something interesting! (albeit disturbing)...
 
Just now got the "sudden static" thing (previous recent incidents were of the sudden silence type).  I turned the volume down.  Just a few seconds later, I checked (without unplugging any USB cable), and the [almost] normal sound resumed on its own (with added background static right now).  In order to restore sound without the added static, I did have to unplug the USB cable again.  Is it possible that I have a faulty tube here? Is any of this "live blow-by-blow" description giving anyone any new ideas?  Thanks.

 

[willkayak4food]

Quote:

 Is any of this "live blow-by-blow" description giving anyone any new ideas?  Thanks.

 
Okay, further unhappy news...
 
Switched USB cable: same problem
 
Switched USB ports (tried both of the other ports - a 2.0 and a 3.0 port): same problem
 
After all this, here's what I seem to know at the moment:
 
1) Cables are not the issue.
 
2) It happens regardless of which USB port is used.
 
3) It happens with or without any other USB port being occupied at the same time.
 
4) It only happens with the HiFiMan EF2A (just now happened again - sudden silence now).  This problem has never happened with the Audioengine D1, nor has it ever happened with the Schiit Bifrost DAC.
 
5) Considering all the above, I also doubt it's "the computer's fault" (or could it still be a particular driver issue--even after the driver uninstall/reinstall?)
 
6) This makes me sad, because the sound of the EF2A is so much more "3D" than that of the Audioengine D1 (which really does feel two dimensional and rather lifeless in comparison).
 
7) If I can't solve this problem with the EF2A, can anyone recommend a reliable, brilliant sounding portable tube DAC/amp that won't make me miss the EF2A too badly?
 
8) I've had enough for the night.  

 

[ClieOS]

I'll still say you should try it on another PC first.

 

[willkayak4food]

Quote:

I'll still say you should try it on another PC first.

 
[10:15 AM] - testing on a different laptop begins now...
 
[10:47 AM] - HiFiMan EF2A failed again!
 
It's not the computer's fault.  It's not the USB cable.  It's not the USB port.  Doesn't seem to be the driver (I'm assuming many other people aren't experiencing this particular problem using the same driver).  I don't know if it has anything to do with these particular tubes (haven't yet received my alternate tubes in the mail, so can't test different tubes just now).
 
Primary suspect: Something about this particular EF2A unit is causing this problem.  I'll call Audio Advisor and see about returning it (will decide if I want a replacement EF2A, or I might look into a different portable tube DAC/amp).
 
Thanks for trying to help!