[zerox202]

Hello, I bought the Asus Xonar Essence ST PCI sound card after hearing so much good stuff about it.
 
But I've encountered a problem with the card.  When I use my IEM to listen music on my computer, I hear a constant hissing noise.  Since the Xonar Essence has such a good signal-to-noise ratio and all the EMI shielding, I'm thinking I shouldn't be hearing this constant background noise.  Of course, I'm a noob and do not fully understand what those terms mean, but it sounds like it has to do with noise.  I'm seriously considering if this is a product defect and if I should RMA this.
 
Here are some details so you guys can help me better:
-The noise is present all the time when the IEM is connected to the port.  Whether I change the sound output to the RCA outputs or others do not matter.  Whenever the computer is on and my IEM is connected to the headphone port, it puts out a constant hissing hum.
-I don't really hear that much of a hum when using other headphones, but I think that's because IEMs get better noise isolation.
-IEM model is Shure SCL-3 if that helps.
 
Also, I know that there is definately noise coming from my sound card because I don't get that sort of noise when I connect to my mp3 player or any other sound source.
 
I've been using the card for nearly five months now, and I've been hearing that noise ever since I bought the card.  I kind of ignored it until now, but now it's really bugging me.  Additionally, I don't think I heard too much of a sound quality improvement from the Xonar Essence over my onboard sound card, maybe I think that because on the other side of my head I think the card is defective.  Anyway, I'm wondering if any of you fellow Xonar Essence users experience this and if you guys think I have a defective product and should RMA it.
 
Thanks a bunch!
Daniel

 

[Hybrys]

SNR really ends up meaning very little, since it's all to do with your power supply in your computer...
 
Either way, I don't think it's a problem with the card, it's the sensitivity of the headphones.  Look into a cheap attenuator, turn up the source, lower the volume at the attenuator.

 

[ROBSCIX]

I wouldn't say it all has to do with your PSU.  If the power was introducing so much noise into the card you would be able to measure it for noise and SNR.  The SNR and noise measurments for this card are exceptional.  The card taps the PSU directly so you don't have the power running through the Mobo and the card has a good power cleaning section also.
 
There were a few around here that built external supplies for their cards but found little in the way of sonic improvments.

 

[zerox202]

How come the sensitivity of the headphones are causing the hum?  I don't get this type of noise when I plug into any other sources.  Even my portable mp3 player does not create noise.  The PSU also seems to be out of the question as ROBSCIX explained.  Will buying an attenuator get rid of the hum?  I don't understand how that will help... it seems like it will degrade the sound quality even more by introducing extra connections.  I'm really frustrated... anymore ideas?

 

[Hybrys]

Quote:

How come the sensitivity of the headphones are causing the hum?  I don't get this type of noise when I plug into any other sources.  Even my portable mp3 player does not create noise.  The PSU also seems to be out of the question as ROBSCIX explained.  Will buying an attenuator get rid of the hum?  I don't understand how that will help... it seems like it will degrade the sound quality even more by introducing extra connections.  I'm really frustrated... anymore ideas?

The PSU ISN'T out of the question.  Robscix explained why it wouldn't be as much of an issue as I'm making it out to be, but even Molex power can be dirty with a medium to low quality PSU.  And the fact that it takes power from both Molex AND motherboard power.
 
Buying an attenuator will get rid of the hum.  How it works is that, the noise is at a certain level, no matter what volume you play sound at.  Thus, you introduce that device, which allows you to cut out x amount of dB (that hum) and you can easily bring up the volume to compensate.  It shouldn't reduce quality by any discernible amount.

 

[zerox202]

I see.  Thank you for the explanation.  I am going to first try getting another unit from ASUS.  If the problem persists, it can be concluded that the problem is introduced by some other component(s) in my computer, such as the PSU like you said.  Then I can use the attenuator trick you told me to alleviate the problem.
 
Thanks!  I'll do an update when I get a new unit.

 

[ROBSCIX]

Try the card on a different set of cans.  If you hear any noise your issue lies elsewhere.
 
Just to clarify, I said the card takes its power for the amplifer sections directly from the molex connector.  NOT from the motherboard.  Only logic signals are taken form the mobo, that is a moot point in this conversation.
 
Did you try basic stuff, like disabling all the recording inputs? If they are floating you will hear a hiss...etc.
 

 

[zerox202]

I am sorry, how do you disable recording inputs?...

 

[ROBSCIX]

Quote:

I am sorry, how do you disable recording inputs?...

click on the recording mixer tab and lower and mute all the faders for mic, Line....  I would also test your card with another set of headphones.

 

[zerox202]

Tried the recording input disabling with no success.  I've tried a full size headphone and don't seem to get the noise.  But then again it does not provide as good noise isolation as the IEM does, so I'm not sure.  And if I recall correctly, I think I heard the noise using a better closed-circumaural design studio headphones at home.  So I must say that the noise is present regardless of the type/design of the headphones.

 

[Hybrys]

Quote:

Tried the recording input disabling with no success.  I've tried a full size headphone and don't seem to get the noise.  But then again it does not provide as good noise isolation as the IEM does, so I'm not sure.  And if I recall correctly, I think I heard the noise using a better closed-circumaural design studio headphones at home.  So I must say that the noise is present regardless of the type/design of the headphones.

Do you remember what those phones were?  It might have just had a low resistance, like your IEMs do, but the other full size having a high resistance.

 

[zerox202]

The one that I  don't really seem to hear the noise is: Sony MDR-V150, some cheap headphone lying around in my dorm room.
The ones that I seem to hear noise: Shure SCL-3 IEM and Audio-Technica ATH-M45.

 

[Hybrys]

MDR-V150 - 24 ohms
 
SCL3 - 26 ohms
 
ATH-M45 - 60 ohms
 
Weird.

 

[zerox202]

It is...  They are all low impedance models and I've been using the correct settings for those phones (Normal Gain for <64 ohms).
I've requested an RMA for the card just in case. 

 

[Hybrys]

Quote:

It is...  They are all low impedance models and I've been using the correct settings for those phones (Normal Gain for <64 ohms).
I've requested an RMA for the card just in case. 

Is there a low gain mode you can try?  Or have you tried high gain, and lower system volumes?
 
I don't own an ST, so I'm running blind here.