[AllsWell]

Man I love this amp, just got it yesterday and out of the box it's sound is impressive. I paired it with my DT990(600) headphones.
 
The only "problem" I have with it is that when I turn the volume nob past halfway point I hear faint pulsing and ringing static noises. This only happens with the gain switches set at 20db.
I think it might be noise from my computer but how can I be certain ?
 
Anyone else experience this and took care of the noise ?

 

[RuthlessVermin]

http://www.head-fi.org/forum/thread/475618/matrix-m-stage-amp-review-simple-cheap-and-excellent/1665#post_7450429
 
Have a look at the posts here and following, and see if that does anything for you.  The sound you describe is different than what I've read there, but perhaps it's of the same cause. 

 

[AllsWell]

Thanks for the link, but that doesn't seem to fix my problem.
I tried tightening the bottom screw on the outside of the case, but I still hear a ringing and buzzing sound. I can't listen to my music because it's quite noticeable.
 
** I just realized that increasing the gain past the default "0" causes the ringing and buzzing noises to happen **
 
Anyone else have this problem and found a solution?

 

[ETAHL]

Have you try a different source?

 

[AllsWell]

Yes, I tried my Ipod touch and there is no ringing or buzzing when I adjust the gain on the Matrix M Stage. This is good. BUT why is there ringing and buzzing when I have it connected to my computer ??

 

[ETAHL]

Sounds like digital noise getting into the audio. I'll bet you are using the sound system build into the motherboard.
You can get a better sound card or better yet, an external DAC.

 

[AllsWell]

Thanks for the help ETAHL,
 
Your right, I am using my motherboard's sound system.
Although, sometimes that digital noise I hear dissapears. (Like right now, its all nice and silent). Do you know why it comes and goes ?

 

[JoetheArachnid]

Here's a solution:

• Buy some tubes.
• Install them in you M-Stage somehow
• Improve tube dampening to prevent ringing.

Just kidding.
 
Anyway, it sounds like a ground loop to me, I had a very similar problem with an amp I built when I connected it to a mains-connected piece of equipment. The throbbing ringing you can hear is the 50/60Hz mains hum. I don't really know what your best options are - I broke my loop by putting 500kohms between signal ground and mains ground, but you might have to do with trying the amp plugged into different AC sockets, buying a new DAC and/or coupling it via optical to break any kind of electrical coupling. I think there are other ways, try a search and see what comes up.

 

[AllsWell]

Thanks man,
 
Lots of interesting solutions/ideas. I'll look into it.

 

[jtam]

Do you use a two-pin plug for your computer? Try to swap the position of the two pins and plug the power again?

 
Quote:

Yes, I tried my Ipod touch and there is no ringing or buzzing when I adjust the gain on the Matrix M Stage. This is good. BUT why is there ringing and buzzing when I have it connected to my computer ??