[creal]

Isn't the alps in the M-Stage grounded at all? As I mentioned before I get some good noise by touching the pot' right about 3/4+, but if I place my finger at the metallic part of the alps housing, the sound out of the IEMs goes off like a lawnmower. Again with my Beyers or AKGs I can't hear anything...
 

 

[the search never ends]

Hi creal, I realize you weren't aiming to use your triples with the M staqge, in answer to grounding yes, it is grounded, although I believe yours is not properly grounded, what you desribe doesn't leave much else, for the sake of trying to coming close to duplicating your situation, I hooked up a few iem's at 20 db gain, nothing except audible hiss at 3/4 volume, (no signal of course) Plastic cover off the potentiometer etc.Considering your  budget, it should be easy enough to correct the grounding problem yourself. Good Luck
 
Edit: Have you tried dynamic iem's and same problem?
Quote:

Isn't the alps in the M-Stage grounded at all? As I mentioned before I get some good noise by touching the pot' right about 3/4+, but if I place my finger at the metallic part of the alps housing, the sound out of the IEMs goes off like a lawnmower. Again with my Beyers or AKGs I can't hear anything...
 

 

[Mad Max]

Quote:

Isn't the alps in the M-Stage grounded at all? As I mentioned before I get some good noise by touching the pot' right about 3/4+, but if I place my finger at the metallic part of the alps housing, the sound out of the IEMs goes off like a lawnmower. Again with my Beyers or AKGs I can't hear anything...
 

 
This is covered earlier in the thread.

 

[creal]

Quote:

Edit: Have you tried dynamic iem's and same problem?

I tried some cheap dynamic iems and the background noise is there too. My question right now: could the reason for the hum/hiss solely be the potentiometer itself?
 
 
Quote:

Originally Posted by Mad Max
 
This is covered earlier in the thread.

I read everything considering ground problems in this thread. It's just I can't hear any noise with my dt880 or even the k530. Why is that the case, just because of the relatively high impedance (Beyer) or the inefficient drivers (AKG)?
 
I'am sorry if it's sound like I just asking dozens of question and don't do any research myself. In the last couple of days I have spent lots of hours to learn more about amps and drivers in this and other boards/blogs. I just wanna be sure since I'am somewhat new to this topic (or at least to the technical aspects of it).
 
Edit: I grounded the pot's case and at least there is no more humming if someone touches the knob but there is still an audible background noise with any iem's I have tried

. That's why I squeezed a wire between the bottom screw and the case and connected it directly to ground. Hoped the toroid would'nt be corretly grounded, but it didn't effected the background noise at all.

 

[Mad Max]

For the toroidal, you unscrew and rescrew the, er, hex screw there several times to wear away excess paint, allowing the screw to better make contact wherever it needs to to make the connection to ground.
When I said that there might be a ground loop somewhere, I did not mean from within the M-Stage.  The issue comes from your home's wiring or from the way you have your equipment connected (as far as power).  That's beyond most of us here, lol.  This is all assuming that you already fixed any issues with the toroidal or volume pot not being properly grounded.
 
In the end, you should still notice a little hiss with IEMs, but with your Beyers and AKGs, you should not
You are right, the inefficiency of your full-sized headphones is the reason why they don't hiss/hum.

 

[creal]

Quote:

For the toroidal, you unscrew and rescrew the, er, hex screw there several times to wear away excess paint, allowing the screw to better make contact wherever it needs to to make the connection to ground.

I already un- and rescrewed the screw a few times, just to check if a lose toroid could be the source of noise. And  the screw is definitely connected  to ground, I checked it with a multimeter.
 
 
Quote:

Quote:Originally Posted by Mad Max /img/forum/go_quote.gif
 
When I said that there might be a ground loop somewhere, I did not mean from within the M-Stage.  The issue comes from your home's wiring or from the way you have your equipment connected (as far as power).

Tried several different wall plugs within our house, unfortunately that didn't changed anything. Maybe I should take that little amp to somewhere else, just to assure that our wiring isn't an issue.
 
Quote:

Quote:Originally Posted by Mad Max /img/forum/go_quote.gif
 
This is all assuming that you already fixed any issues with the toroidal or volume pot not being properly grounded.

 
Well, at least there is no additional hum if I touch the pot right now

.
 
 
Quote:

Quote:Originally Posted by Mad Max /img/forum/go_quote.gif
 
In the end, you should still notice a little hiss with IEMs, but with your Beyers and AKGs, you should not
You are right, the inefficiency of your full-sized headphones is the reason why they don't hiss/hum.

Most people and reviews said their M-Stage doesn't hiss at 0 gain if they keep the volume just below max, even with their most sensitive custom IEMs. That's obviously not the case here - although I tried less efficient IEMs too.

 

[Chris J]

Quote:

I already un- and rescrewed the screw a few times, just to check if a lose toroid could be the source of noise. And  the screw is definitely connected  to ground, I checked it with a multimeter.
 
 
Tried several different wall plugs within our house, unfortunately that didn't changed anything. Maybe I should take that little amp to somewhere else, just to assure that our wiring isn't an issue.
 
Well, at least there is no additional hum if I touch the pot right now

.
 
 

Most people and reviews said their M-Stage doesn't hiss at 0 gain if they keep the volume just below max, even with their most sensitive custom IEMs. That's obviously not the case here - although I tried less efficient IEMs too.

 
Try getting one of those plug-in receptacle testers from the hardware store to ensure that your house wiring is grounded properly and Line and Neutral are correctly oriented.
Whatever you do, do not cut off the ground pin on the AC cord!

 

[creal]

Quote:

Whatever you do, do not cut off the ground pin on the AC cord!

Cutting off protective earth would be indeed a pretty stupid idea, especially if your favorite electronic device comes with a metal housing

.
 
Btw: both N and PE seems to be conntected properly. Therefore something amp-internal has to be wrong.

 

[wilky61]

Been listening to my FLAC collection with AKG Q701 by way of a FiiO E17 for the last month... finally decided to sell my E17 (for $30 more than the price for which I bought it, no less) and to upgrade to the Matrix M-Stage.

 
Hopefully I won't have to wait too long on the postage for the device to arrive. I have never owned anything like a desktop amp/DAC before (the E17 was my first such purchase) so I am really looking forward to playing around with my new toy and the LM4562 I ordered simultaneously from eBay.
 
Probably gonna buy a high-grade USB cable while I'm at it... I'm thinking of getting one of those silver-cored Pangea Audio USB cables from Amazon because I have a bunch of credit there.
 
 
 
Also, one noob question to which I'm pretty sure I know the answer, you would never want to use the line-out on the back of the M-Stage to power headphones due to output impedance, right?

 

[genclaymore]

One of the RCA's on the rear is for fixed level output for plugging into a powered speaker system.  You would use the Front 6.3 jack for the headphone's. Your AKG should had came with a 6.3 converter plug.

 

[Greeni]

Got the M-stage, after some run-in I could relate to others' comment that this is a dark sounding amp.
 
It is difficult to describe and we have different terminology, but it is not a roll off of treble as such. It is more like a tonality thing, as if the tonal colors are stripped away and left with a monotonous blackish tone.
 
Mine has been owned for a week only but now put on for sale forum, it is a 230 volt version for Europe. Not that it is bad, just that my other existing amps may serve me better.

 

[chicolom]

Quote:

Been listening to my FLAC collection with AKG Q701 by way of a FiiO E17 for the last month... finally decided to sell my E17 (for $30 more than the price for which I bought it, no less) and to upgrade to the Matrix M-Stage.

 
Hopefully I won't have to wait too long on the postage for the device to arrive. I have never owned anything like a desktop amp/DAC before (the E17 was my first such purchase) so I am really looking forward to playing around with my new toy and the LM4562 I ordered simultaneously from eBay.

 
While the M-stage is a good amp, the DAC in the M-stage won't be as good as the one in the E17.

 

[wilky61]

So, do you think I may be disappointed in the M-Stage?
 
Quote:

 
While the M-stage is a good amp, the DAC in the M-stage won't be as good as the one in the E17.

 

[chicolom]

Quote:

So, do you think I may be disappointed in the M-Stage?

 
Not with the amp, but it only has a $30 DAC in it, so I don't think it's fair to judge its performance based off using it's own DAC.  I think it's better paired with an external DAC.

 

[wilky61]

Okay, sorry I'm sure it's been asked before, but now you're going to have to give me a hint -- what are some external DACs that Head-Fi'ers have paired with the Matrix M-Stage before? Any recommendations? Thanks.
 
Quote:

 
Not with the amp, but it only has a $30 DAC in it, so I don't think it's fair to judge its performance based off using it's own DAC.  I think it's better paired with an external DAC.