[rasmushorn]

As far as I can read back in the threads NOONE with a Mac-computer has the problem? Am I right?
Sounds like it is a compatibility/noise isolation issue with certain laptops.

 

[Fantoon]

Post 332 indicates that there is such issues with Mac users.
 
Quote:

As far as I can read back in the threads NOONE with a Mac-computer has the problem? Am I right?
Sounds like it is a compatibility/noise isolation issue with certain laptops.

 

[rasmushorn]

Quote:

Post 332 indicates that there is such issues with Mac users.
 

 

OK - I might be wrong then 

 

[honmashinsei]

I just received mine! uDac-2, black version, orderered from Hifi to Go in the Netherlands. Like I reported before I was afraid of the tone issue, but the store insured me that I would get a full refund if I experienced the tone.
 
Just plugged it in: at first with my Alessandro MS-1i. No tone! Nothing! No click when I turn the unit on, no hiss when I turn the volume all the way up, just nothing.
Then: MEElectronics M6: No tone! I hear a slight click when I turn the unit on, and a little hiss when I turn the volume control way up. But that's all there is, I'm definately not hearing any of the tones posted earlier.
After that: Sony MDR-CD3000. No tone! No click when I turn the unit on, but a little hiss when I turn the volume control way up. But that's all there is, I'm definately not hearing any of the tones posted earlier.
 
So, I am very happy with my unit. I cannot hear the tones that were posted earlier. If there is a tone, it would have to be one over 16 kHz, cause I cannot hear anything above that frequency.
 
Here is the questionnaire:
 
1.  Can you hear the tone? ( if no, jump to question 9) > no.
2.  Is the tone louder than the background hiss? (a feel for how loud it is)
3.  Does the tone change volume with the volume knob turning?
4.  Estimate the frequency of the tone
5.  Does the tone frequency change with different headphones?
6.  Try different usb ports on the computer, does the tone change volume or frequency or is it identical on every port?
7.  Does the tone occur anytime the udac2 is plugged in and on, whether it's playing anything or not?
8.  Is there a tone if you plug it into a usb charger or hub without being connected to a computer?
9.  List the computer(s) it is connected to and if any hub or extension cable is in between.
Sony Vaio FW11S laptop. It is connected with an 220V power cable (European) to the power grid, with a connector box in between. Running the laptop on battery does not change anything. Using Windows 7 Ultimate.
10. List the usb cable you are using it with. Stock USB cable that came with uDac-2.
11.  List the headphones you hear and don't hear it with. See above (MS-1i, MEElec M6, Sony MDR-CD3000)
 
I'd be happy to answer any questions or do some more testing. Let me know.
 
(Oh and by the way, this is my first DAC and I must say I'm really impressed by the difference! Rediscovering my music again!

)
 
 

 

[mattiasottosson]

Hi.

I just received my uDAC-2 and I noticed the tone immediately and it's in fact very noticeable if you listen to music where the sound picture isn't very complex. I tested it against a tone generator and it's close to 2000 Hz.

I tired different ports on my computer (Macbook Pro 15" Core i7), and it's the same tone. It also stays unchanged if you pull the plug and run it on battery. Connecting it to directly my iPhone usb-charger generates the same tone.

However, i found a way to eliminate the sound completely. If i plug the uDAC into my Kengsinton usb hub without having the external power adapter to the usb hub connected, the tone goes away and I also noticed one notable thing. I have a couple of units connected to the hub (keyboard, Wacom board, iPhone dock etc). If i remove one by one i can hear the tone coming back, starting at a low frequency that goes higher by every unit that I disconnect.

It definitely has something to do with the amount of usb power allocated. When the 500 mA of power to the usb hub gets shared by the connected units, the sound goes away, but as soon as the power cord is plugged back in, giving every port a 500 mA minimum, the sound comes straight back.

The standard should be 500 mA (from what I learned), but it varies a lot from computer to computer. Maybe that's why some notice the tone and some don't. Also, using different headphones maybe makes the unit require more or less power as well.
 
1.  Can you hear the tone? ( if no, jump to question 9) > yes
2.  Is the tone louder than the background hiss? (a feel for how loud it is) > no
3.  Does the tone change volume with the volume knob turning? > no
4.  Estimate the frequency of the tone > Close to 2000 hz
5.  Does the tone frequency change with different headphones? > yes
6.  Try different usb ports on the computer, does the tone change volume or frequency or is it identical on every port? > Read above
7.  Does the tone occur anytime the udac2 is plugged in and on, whether it's playing anything or not? > yes
8.  Is there a tone if you plug it into a usb charger or hub without being connected to a computer? > yes
9.  List the computer(s) it is connected to and if any hub or extension cable is in between.
Macbook Pro core i7 with and without kengsinton usb-hub
10. List the usb cable you are using it with. Stock USB cable that came with uDac-2.
11.  List the headphones you hear and don't hear it with. Grado SR 125, Shure SE 420
 

 

[mattiasottosson]

I just noticed that using the free usb port instead of the shared ones in the hub makes the uDAC generate a noticeable higher volume. Strange.

 

[mr-teatime]

i can second that.
 
funny enough i was testing a very very similar setup last night ...
if you connect the external power connector to the usb hub the tone is louder and higher
 
that said, if you connect a very long usb cable (higher resistance) to the UDAC2 w/o any hub and its external power supply, you can almost eliminate the tone ...

 

[replytoken]

Quote:

However, i found a way to eliminate the sound completely. If i plug the uDAC into my Kengsinton usb hub without having the external power adapter to the usb hub connected, the tone goes away and I also noticed one notable thing. I have a couple of units connected to the hub (keyboard, Wacom board, iPhone dock etc). If i remove one by one i can hear the tone coming back, starting at a low frequency that goes higher by every unit that I disconnect.
 

I had a very similar experience when I was trying different combinations, and tried to post a brief summary of them a few days ago.  I did not have a chance to check out if this sound was still audible through the RCA outs in these set-ups.  Did you get a chance to check that as well?
 
--Ken
 

 

[kite7]

Just tried the uDAC-2 on my Toshiba laptop with battery then AC adapter and other computer with generic power supply, no hiss at all. Absolute silence

 

[shaddix]

NuForce was kind enough to refund my shipping costs for BOTH times I sent it back to them. They actually just sent me $10 via paypal, quite impressive. Hopefully this tone fiasco will get figured out soon.

 

[mattiasottosson]

Quote:

I had a very similar experience when I was trying different combinations, and tried to post a brief summary of them a few days ago.  I did not have a chance to check out if this sound was still audible through the RCA outs in these set-ups.  Did you get a chance to check that as well?
 
--Ken
 

No, unfortunately not. I tested the dac at work and had no equipment available. I will buy a cheap RCA to stereo plug adapter asap and try that out.

 

[replytoken]

Quote:

No, unfortunately not. I tested the dac at work and had no equipment available. I will buy a cheap RCA to stereo plug adapter asap and try that out.

 
No need to rush out and purchase stuff on my account.  I was just curious to hear somebody else's opinion on this setup before I try it with my uDAC-2.
 
Having read the mixed results in the last few posts, I am going to "go long" and ask if there are any uDAC-2 owners in the greater Seattle area that are not experiencing this problem.  If so, I would like to get together with you and compare uDAC-2's, cables and/or computers.  I know it is a long shot, but PM me if that's you.
 
Thanks,
 
--Ken

 

 

[jasonl]

We have checked with worldwide distributors and so far, the problem seems to be isolated in Sweden

We have asked the distributor to send the few uDAC-2 that have problems back to factory at the fastest possible express mail. If you are experiencing problem, please contact our support directly so that we can track it with help desk system.
 
Quote:

Jason,
 
Thank you for weighing in at this point in the thread.  And more importantly, thank you for [size=10pt]acknowledging [/size]that the noise some of us are hearing may be related to earphone compatibility.  The uDAC-2 is a great product that can produce some incredible sound.  Its just that this situation its very frustrating for those of us who are experiencing these noises, for whatever reason.  Even if nothing can be done about this situation, I am guessing that those of us who are experiencing these noises were hoping for some validation/confirmation from NuForce.  I will not speak for others, but I can understand, and am often times willing to accept, trade-offs in a product's design.  Over the years I have learned to live with a very high nosie floor from tube preamplifiers feeding my solid state amplifier.  It would be great if there were virtually no noise floor, but that's not the case.  So, given the sound they produce at their price point, I have learned to use attenuators and live with them as they are.  As their are many variables in play here, and at present it seems like just a small number of us are hearing noise (relative to the total number of untis produced), I can understand that you are not able to say much more other than to remind people that you have a very liberal return policy.  I do, however, hope that if you are able to personaly experience the noise that we are hearing, and are able to identify a solution, that you will remember us.  I believe that reputations and customer loyalty are built upon doing the right thing.  Offering a trial period and liberal return poicy at the time of sale is certainly the right thing in my book.  Remembering me, and my needs, after the sale is "going the extra mile", and something that generates a large amount of goodwill.
 
--Ken
 

 

[jasonl]

It is not that we are doubting you. None of us can hear the tone at our office. Other users have posted online that they don't hear the tone either.  We have heard nothing from Hong Kong, Japan (and these are two countries with picky audiophiles), France.  Only a few complains from USA, a few more from Sweden. 
All we can do now is to retrieve those 6 units from Sweden for thorough testing at factory.  I remembered one US customer returned a uDAC-2 with complain of high pitch tone, but we can't hear it.
 

Another customer here to whine about the whine.
 
I hear it on everything from Sennheiser MX500s to JH13s. I've tried it through my USB hub, without it, plugged into a USB charger or a laptop running only on battery. Whine every time.
 
And everything in the configurations I've tried is identical to the setup of the uDAC 1 it replaced (which didn't produce any such noise).
 
Sorry, but there exists a design flaw and/or a production variance. To assume anything else is to bury one's head in the sand.
 
Edit: And it's loud enough that I can hear it over music.

 

[jasonl]

I suggest that if anyone can hear loud tone, lets not beat this issue to death. Contact our support, we will get the item back for testing.
Jason
 
Quote:

It is not that we are doubting you. None of us can hear the tone at our office. Other users have posted online that they don't hear the tone either.  We have heard nothing from Hong Kong, Japan (and these are two countries with picky audiophiles), France.  Only a few complains from USA, a few more from Sweden. 
All we can do now is to retrieve those 6 units from Sweden for thorough testing at factory.  I remembered one US customer returned a uDAC-2 with complain of high pitch tone, but we can't hear it.