[kellte2]

It is definitely grounded.  Would never cut a pin off a AC adapter/power cable.

 

[Chris J]

  It is definitely grounded.  Would never cut a pin off a AC adapter/power cable.

 
The problem must be with the gear plugged into the matrix.
I've never had the problem you've described and I have plugged various pieces of equipment into my M Stage.

 

[kellte2]

I loosened the screw on the knob and the buzz went away.  Strange, but i'll take it.

 

[Chris J]

 

[project86]

I've got the new version on the way so I can have a quick listen, maybe compare it to the original and see how it does. The Matrix USA rep asked Matrix HQ about what exactly the differences are between the models. This is the reply given:
 
 
M-stage HPA-2:   
 
1. Gain is now fixed (maximum value is +15dB）no more gain switches on the bottom of the unit.
2. Added headphone protection functions:
    a. If direct current is detected the headphone output is instantly muted.
    b. When the unit is turned on or off the audio is muted to prevent 'pops' & 'clicks'.
 
M-stage HPA-2 USB:
 
1. XMOS USB interface chip, support for up to 24bit/192kHz, ASIO driver support, and a LME49720 OpAmp replaces the OPA2134 OpAmp.
 
So I can't imagine the sound being too drastically different. Remove the gain switches from the signal path, and then add the DC servo (or whatever they did for protection), and you're probably right back where you started in terms of signal path complexity. The +15dB gain seems fine to me - I mostly used the original on 10dB anyway. 
 
The USB version seems to be a more substantial improvement. Since they don't list a different DAC chip we can assume the PCM1793 is still in play. XMOS plus PCM1793 plus the quality power supply on board, and the LME49720 which is always a crowd pleaser.... For the $40 price difference, I can't imagine getting a stand alone USB DAC that could come anywhere near it. But we'll see. 

 

[Chris J]

So we can surmise that the headphone amp sounds the same as it did before.
Fixing the gain at +15 dB sounds more like a cost reduction than anything, i.e they deleted the DIP switches.

 

[chicolom]

Interesting about the removal of dip switch gain...

 

[Chris J]

Hopefully they improved the volume control so it tracks well at low volumes

 

[project86]

  So we can surmise that the headphone amp sounds the same as it did before.
Fixing the gain at +15 dB sounds more like a cost reduction than anything, i.e they deleted the DIP switches.

 
We'll see. I suspect there may be some other minor tweaks involved that have not been mentioned. For example, the voltage adjustment switch is now on the left side of the enclosure. So obviously something in the power supply has been reworked to accommodate that. Enough to make a change in the sound? Dunno yet. 
 
The gain adjustment went away but they added DC protection circuit. So the complexity is still roughly the same as it always was, give or take. 
 

  Hopefully they improved the volume control so it tracks well at low volumes

 
I'll definitely check this. My original M-Stage had good tracking but I've heard from others who had issues. So maybe it varies from one unit to the next? Potentiometers are all unique (even within the same batch) so it's very possible. 

 

[Chris J]

   
We'll see. I suspect there may be some other minor tweaks involved that have not been mentioned. For example, the voltage adjustment switch is now on the left side of the enclosure. So obviously something in the power supply has been reworked to accommodate that. Enough to make a change in the sound? Dunno yet. 
 
The gain adjustment went away but they added DC protection circuit. So the complexity is still roughly the same as it always was, give or take. 
 
 
I'll definitely check this. My original M-Stage had good tracking but I've heard from others who had issues. So maybe it varies from one unit to the next? Potentiometers are all unique (even within the same batch) so it's very possible. 

 
If they added a 120/240 Vac switch for International compatibility to the M Stage, then they specified a different transformer, which won't necessarily alter the sound of the M Stage.

 

[project86]

   
If they added a 120/240 Vac switch for International compatibility to the M Stage, then they specified a different transformer, which won't necessarily alter the sound of the M Stage.

 
Yeah, we'll have to see. I have a loaner on the way for a quick comparison - won't be a full review or anything, just trying to get a general idea of what's going on with it. 

 

[Chris J]

   
Yeah, we'll have to see. I have a loaner on the way for a quick comparison - won't be a full review or anything, just trying to get a general idea of what's going on with it. 

 
To me, the whole thing sounds like a USB DAC upgrade plus a facelift?

 

[project86]

   
To me, the whole thing sounds like a USB DAC upgrade plus a facelift?

 
Could be. It's definitely more of a significant update on the USB side versus the amp side - which honestly makes sense as the amp was always far better than the DAC option. 
 
In other news, Matrix has new info on the their updated Mini- model. The surprising development is the addition of a mini-i Pro, which is an upgraded version with more capabilities.
 
Mini-i is $379, has the dual AD1955 DACs and an XMOS async USB section supporting 24-bit/384kHz signals.
 

 

 

 

 
 
 
 
The mini-i Pro ($519) trades the Analog Devices DACs for an ESS Sabre ES9016 chip. It has the same USB setup but now supports DSD and DXD thanks to the DSD capable DAC chip. 
 

 

[beaver316]

Just thought I'd post here that I'm considering selling my M-stage. If anyone here is interested you can see details here.

 

[zting]

 
Yeah, we'll have to see. I have a loaner on the way for a quick comparison - won't be a full review or anything, just trying to get a general idea of what's going on with it. 

 


I would be extremely interested in hearing your opinion on the new mstage hpa2