FIRST IMPRESSIONS: NEW Nuforce uDAC-2 with 24/96 - USB DAC AMP with line out and S/PDIF out
Sep 27, 2010 at 12:06 PM Post #271 of 877

rasmushorn

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Received - plugged in and playing! No tone or hiss at all with my SR325i.
 
Sep 27, 2010 at 12:34 PM Post #272 of 877

replytoken

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Sep 27, 2010 at 1:22 PM Post #273 of 877

Armaegis

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You can make your own impedance adapter for about $10 ($20 if you use good parts). I've made a few for myself and some local guys.
 
Sep 28, 2010 at 1:29 PM Post #274 of 877

IsoOctane

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Quote:
You can make your own impedance adapter for about $10 ($20 if you use good parts). I've made a few for myself and some local guys.


Any pointers on this? Would two resistors in series with the channels be enough? Obviously the values of the resistors should be as closely matching as possible, and I guess they should be able to handle some current without overheating and not contain any hidden capacitance or something?
 
I decided to keep the uDac as I mostly use it with my amp anyway. But for the peace of mind, and since I can return them at no cost, I bought a second unit for comparison. I wasn't expecting much, and yeah, the noise is there, about the same volume but slightly lower frequency. I think lower frequency means it'll be less intrusive so I might keep this new one.
 
While one might theoretize about a bad batch or something, in fact as far as I can see no-one here has reported NOT hearing the tone with headphones of low impedance (say, under 32 ohm) and high sensitivity. I checked that some of the in-ears people were not having the noise with actually had impedances around 40-50 ohms.
 
Sep 28, 2010 at 1:57 PM Post #275 of 877

bcwang

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Quote:
 
While one might theoretize about a bad batch or something, in fact as far as I can see no-one here has reported NOT hearing the tone with headphones of low impedance (say, under 32 ohm) and high sensitivity. I checked that some of the in-ears people were not having the noise with actually had impedances around 40-50 ohms.
 
 


I can't hear it with the Monster Turbine Pro copper or the SE530, but after checking I notice both are above 32 ohm.  I have a e4g I will check later which is 29 ohm, but is not as sensitive.  I hear a lot of hiss with the se530 but no tone.
 
Maybe people who hear the tone should post what headphone they are using so we can see if all the time those combinations are present, so is the tone.  Also, has anyone heard the tone with any full size headphone?
 
 
Sep 28, 2010 at 4:35 PM Post #277 of 877

replytoken

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Although I posted in previously in this thread, I'll post again for convenience:
 
Etymotic ER-4P - Noise is clearly heard
 
Etymotic ER-4P w/S-cable adapter - Noise is greatly reduced, but present
 
Senn HD-600 - No noise present
 
RCA Line-outs - No noise present
 
All listening was casual, nothing scientific.
 
--Ken
 
Sep 28, 2010 at 4:48 PM Post #278 of 877

grokit

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Sep 28, 2010 at 7:58 PM Post #279 of 877

shaddix

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http://www.head-fi.org/forum/thread/375547/sennheiser-ie8-appreciation-thread/6540?#post_6925770
 
 
Quote:
Strange - my uDAC-2 doesn't hiss even with my most sensitive IEM (ES3X, W3, etc) that hiss on other amps.  And my IE8 did not hiss with my noisiest amp that hisses noticeably with my most sensitive IEM (ALO Amphora and AMP3).  I've never felt the IE8 were a hissy IEM.  I suspect there is a problem with the uDAC-2 and it should be okay after you have it replaced.

 
 
As for me, I heard that tone loud and clear over my music using HD595s(50 ohm version) and IE8s
 
Quote:
While one might theoretize about a bad batch or something, in fact as far as I can see no-one here has reported NOT hearing the tone with headphones of low impedance (say, under 32 ohm) and high sensitivity. I checked that some of the in-ears people were not having the noise with actually had impedances around 40-50 ohms.

 
Sep 29, 2010 at 2:39 PM Post #281 of 877

bcwang

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You mean 3 different samples of udac2?  Please list which 2 phones and 2 cables you were using as well.
 
Also, I think people should list what kind of computer they are plugging their machine into, and whether it is going through a hub or not.
 
I tried with the shure e4 last night and still hear no tone, just hiss as usual.  This is puzzling.
 
I know with the HDP, if I plug in the USB and analog cables at the same time, it may create a buzz/tone type sound depending on the source the analog cable is coming from.  This seems like a bridged loop type problem where you have an electrical loop between different components.  With the udac this shouldn't be happening since it is only a single cable, but who knows if there is some interaction causing this to occur.  Maybe the people who hear this with multiple units and headphones do so because they are still using it in the same system which might be the cause of this problem.  If the tone is clearly audible and not in a frequency range many people can't hear, all of us should be hearing it, but this doesn't seem to be the case. 
 
 
Quote:
I'm hearing the tone/noise on three different devices with 2 phones and 2 cables
frown.gif

 
Sep 29, 2010 at 2:46 PM Post #282 of 877

bcwang

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Let's all try to answer this list and maybe we can conclude something:
 
1.  Can you hear the tone? ( if no, jump to question 9)
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.
10. List the usb cable you are using it with.
11.  List the headphones you hear and don't hear it with.
 
Sep 29, 2010 at 3:30 PM Post #283 of 877

dkimxd

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1. Yes
2. No
3. No
4. don't know
5. No
6. No
7. Yes
8. Yes, but at a lower frequency
10. The one that came with the udac-2
11. I can hear it with skullcandy iems, and  cannot hear it with grado sr60s
Quote:
Let's all try to answer this list and maybe we can conclude something:
 
1.  Can you hear the tone? ( if no, jump to question 9)
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.
10. List the usb cable you are using it with.
11.  List the headphones you hear and don't hear it with.

 
Sep 29, 2010 at 7:43 PM Post #284 of 877

JackG

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1. No.
 
9. Dell Studio XPS desktop, no hub/extension.
 
10. The cable that came with the uDAC.
 
11. No tone/noise here with my Panasonic HJE900 IEM, Grado SR60i, or AT ATH-M50.
 
Quote:
Let's all try to answer this list and maybe we can conclude something:
 
1.  Can you hear the tone? ( if no, jump to question 9)
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.
10. List the usb cable you are using it with.
11.  List the headphones you hear and don't hear it with.

 
Sep 29, 2010 at 8:16 PM Post #285 of 877

bcwang

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1.  No
 
9.  HP xw4600 workstation running xp64, custom built core2 duo on gigabyte ga-p35-ds3r running win7, 2010 macbook pro 13"
 
10. belkin 3 ft, nuforce impulse 1.8M, wireworld starlight 1M, generic 1 meter
 
11. Don't hear a tone with any of these, though I hear hiss with the first 3: se530, monster turbine pro copper, shure e4g, shure srh840, grado hf1, senn hd800
 
Quote:
Let's all try to answer this list and maybe we can conclude something:
 
1.  Can you hear the tone? ( if no, jump to question 9)
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.
10. List the usb cable you are using it with.
11.  List the headphones you hear and don't hear it with.

 

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