[dudefromearth]

I purchased it for my HD800s. The soundstage was great at first, but now it is very thin, only existing in the middle. The "left and right of the soundstage" is non-existent. It is all focused in the middle.
 
My set up is:
 
HD800 > Matrix M-Stage > RCA Cables > Nuforce uDAC > USB Slot
 
To clarify the problem, I plugged the beats by Dr Dre into a 1/4 jack from their native 1/8 jack and inserted that into the Matrix-M Stage: No soundstage. I then put the 1/8 jack of the headphones directly into the computer and the soundstage spreads to the left and right speakers. I then plugged the 1/8 jack of Beats into the uDAC and inserted the uDAC into the USB slot, the soundstage is there.
 
Beware when buying the Matrix M-Stage from ebay.  It can mess up easily.

 

[kite7]

How can you relate a random defect being a result from purchasing from ebay? You should contact the seller to see what he can do for you.

 

[hodgjy]

Open the amp up to see if the capacitors have swelled or burst.  I've heard of cap malfunctions doing strange things to the soundstage.

 

[Currawong]

If the sound is entirely coming from the middle, with no obvious left and right separation, then you're hearing the music in mono, not stereo. Coul the left and right channels be crossed somehow? Are all the plugs in securely?

 

[dudefromearth]

Quote:

If the sound is entirely coming from the middle, with no obvious left and right separation, then you're hearing the music in mono, not stereo. Coul the left and right channels be crossed somehow? Are all the plugs in securely?

Yes, the plugs are in securely.
 

 

[Currawong]

Either in your computer software or physically somewhere in the chain, the left and right channels have crossed, giving you a mono signal, going by your description.  You might wish to go through absolutely everything to see if you can't figure out where things have become crossed.

 

[majkel]

You could have lost the ground pin continuity as well, for instance on the jack socket soldering. Try another pair of headphones to see if the effect repeats and comes from the amplifier. Shorting of both channels in the amplifier is less probable.

 

[bhd812]

check the settings on your computer, esp in the playback devices if you're using windows and also try a different source and different cables.

 

[Frank I]

I have my Matrix for over four months played 8-12 hrs a day without a glitch. You should check all your connections and see if its connected properly or send it in for repair.

 

[The Monkey]

Did you press the soundstage button?

 

[RuiCanela]

Quote:

Did you press the soundstage button?

Yes, you must check it!!!..

 

[dudefromearth]

How much would it cost to get repaired?

 

[leeperry]

 

Did you press the soundstage button?

 
It's enabled by default in the versions whose volume pot goes up to 11.

 

[francisdemarte]

Might be a solder joint break in the headphone jack. Try jiggling the jack and see if you hear anything different.