[zting]

Isn't the M-dac in a completely different price class, and apple to oranges all around? Also-XMOS rocks-it's the main USB method that my SBT loves.

John-from strictly an amp perspective-how does the HPA-2 compare to the original, assuming the same opamp is used?

-Daniel

They are but mdac is built as a DAC and not as a pure amp which the mstage is. I thought the mstage amp bebe atleast as good but with a different colouration?

But then does it matter with the DAC in the mstage as I am using the mstage purely purely as an amp?or am I missing something?

 

[Maxvla]

The HPA-2 is fixed gain of +15dB. HPA-1 is 0 to +20dB.

 

[Maxvla]

Correction from Matrix on the opamp included with HPA-2, all versions have the OPA2134. The USB DAC model does not have a different opamp. Perhaps John swapped it and forgot?

Another difference between the HPA-1 and HPA-2 is that the voltage is now switchable, so it should work almost anywhere in the world.

 

[conquerator2]

Correction from Matrix on the opamp included with HPA-2, all versions have the OPA2134. The USB DAC model does not have a different opamp. Perhaps John swapped it and forgot?

Another difference between the HPA-1 and HPA-2 is that the voltage is now switchable, so it should work almost anywhere in the world.

That's strange it clearly says in the description that it uses the LME49720...
Are they lying then?
How would I change an opamp?
Thanks

 

[hellexecutor]

That's strange it clearly says in the description that it uses the LME49720...
Are they lying then?
How would I change an opamp?
Thanks

New USB-module has an op-amp too, and it's LME49720.

 

[conquerator2]

 
New USB-module has an op-amp too, and it's LME49720.

Was he talking about the older model then?

 

[hellexecutor]

  Was he talking about the older model then?

 
I think it's just a little mixup here. LME49720 is the only opamp mentioned in the description of HPA2 on Matrix website so it was easy to think that it replaced "old" OPA2134.

LME49720 op-amp used in new USB-DAC module (see pic http://matrix-digi.com/uploads/allimg/introduction/hpa-203.jpg, to the right of DAC). The Amp-part uses OPA2134 in both USB and non-USB versions of HPA2, as well as in older HPA1. That's my thoughts

 

[chicolom]

That's strange it clearly says in the description that it uses the LME49720...
Are they lying then?
How would I change an opamp?
Thanks

 
Maybe just the DAC section uses the LME49720.  I see no mention of that opamp on the non-DAC model page.
 

 
 
Changing the opamp is easy, you just take out the top 4 screws (you'll need an allen wrench for the front ones) and then pull the top off.  Then you pull the opamp out and replace it with another.  Make sure the opamp goes in the right direction.  The opamps have a little indent and a dot in the top left corner, and I believe those should be facing the amps inputs (the back of the M-stage).  So if your looking at the front of the M-stage with the volume knob facing you, the opamp should have the indent farthest away from you and closer to the rear of the M-stage.
 
Like this:
 

 
 
 
 
 
 

 
 
 
 
 
One last thing...
 
I get the sense that your already pre-biased towards thinking that the OPA2134 opamp is bad, but IMO it sounds perfectly fine.  I think some people take any issues they have with the sound on a piece of gear and then blame it all on the first interchangeable part.  I see this happen a lot with the Fidelio X1 - people listen to it and then blame any issues they have with the sound on its stock cable (with it's 1 ohm of extra resistance

). Add in a dose of placebo and expectation bias, and all their issues with the sound seem to magically get fixed as soon as they use a different cable (the other day a new X1 owner said he heard a "night and day difference" when he switched out cables).  The cable starts becoming the scapegoat for everyone's issues.  After this process of people blaming their problems on the cable repeats for a while, people eventually start labeling the stock cable as "lousy","garbage", "trash", etc.  New people who get the headphones read the negative remarks and often just conform to the idea that the cable actually is garbage, and then they voice it themselves - and the cycle repeats.
 
I think the same thing happens with the M-stage and its stock OPA2134 opamp.
 
 
Feel free to play around with changing them, but don't be surprised if the differences in opamps turn out to be very minor.

 

[hellexecutor]

[double post]

 

[conquerator2]

   
Maybe just the DAC section uses the LME49720.  I see no mention of that opamp on the non-DAC model page.
 

 
 
Changing the opamp is easy, you just take out the top 4 screws (you'll need an allen wrench for the front ones) and then pull the top off.  Then you pull the opamp out and replace it with another.  Make sure the opamp goes in the right direction.  The opamps have a little indent and a dot in the top left corner, and I believe those should be facing the amps inputs (the back of the M-stage).  So if your looking at the front of the M-stage with the volume knob facing you, the opamp should have the indent farthest away from you and closer to the rear of the M-stage.
 
Like this:
 

 
 
 
 
 
 

 
 
 
One last thing...
 
I get the sense that your already pre-biased towards thinking that the OPA2134 opamp is bad, but IMO it sounds perfectly fine.  I think some people take any issues they have with the sound on a piece of gear and then blame it all on the first interchangeable part.  I see this happen a lot with the Fidelio X1 - people listen to it and then blame any issues they have with the sound on its stock cable (with it's 1 ohm of extra resistance

).  All their issues with the sound seem to magically get fixed as soon as they use a different cable, and the cable becomes the scapegoat for everyone's issues (the other day a new X1 owner said he heard a "night and day difference" when he switched out cables).  After this process of people blaming their problems on the cable repeats for a while, people eventually start labeling the stock cable as "lousy","garbage", "trash", etc.  New people who get the headphone and read others negative remarks often just conform to the idea that the cable actually is garbage, and they voice that and the cycle repeats.
 
I think the same thing happens with the M-stage and its stock OPA2134 opamp.
 
Feel free to play around with changing them, but don't be suprised if the differences in opamps turn out to be very minor.

 
Thanks Chico.
Yeah, that's the one thing I hate about our community, we tend to exaggerate A LOT.
And because most of the times there is no chance for me try most of the products I buy beforehand, I have to go by my most reliable source [which is you & the rest]
The thing is, more often than not, I end up just that, while my own impressions are different.
"This op-amp, is muddy and tizzy and the soundstage s unnatural and shrunk, but THIS opamp makes the treble crystal clear and the soundstage very spacious" "Mkay, let me try that."switches the opamps" but the different is so small!"
This is how it usually turns out for me.
 
I still love the community as most of the decisions [head-fi] related turned out very well thanks to it, but the exaggeration shows.
 
And then there is the expectation. Sometimes, when you expect something to sound different, you can hear it [well aka placebo or expectation bias] even though in reality its not really like that.
 
Rest assured, I'd like to avoid changing anything at first as I don't really like altering stuff [using different exchangeable parts, using EQ, etc] as that's not the way it was meant to sound. I am not against changing opamps [and thanks to your great guide, it'd be a breeze now :]] but I'd try the stock one for some time and try to forget the impressions I've read and try to make my own mind.
 
Thanks again for the guide & tip :]
 
I am sure I'll be happy.

 

[Chris J]

Changing the Op Amp in the M Stage makes a very subtle difference.
But it's easy to do and doesn't cost a lot of money, so you may as we'll try it out for yourself!

 

[vian]

Sorry to disappoint you, but it has no gain switch.
I know it, because I own the usb version of this new HPA-2.
 
But that's the only downside.
It's a great amp, the sound is very musical and engaging. I use it via it's USB input and paired with my AKG Q701, and they seem to be a great match so far.
The onboard DAC is a steal for that extra 40 dollars. 

 

[project86]

Bingo, a few people hit on it already. The HPA-2 amp output uses the OPA2134, on both the USB version and the amp-only model. I didn't know that until recently (I never opened the case on my loaner). The literature I was given mentioned the LME49720 for the USB version so I just assumed they meant in the output stage. 
 
Let me recap for a sec - my original M-Stage is on loan far, far away, so I couldn't compare it to the HPA-2. But I was able to borrow last year's model from a friend. He told me it had a stock OPA2134 so I thought I was comparing that to the HPA-2 with LME4920. Boy was I mixed up. I stand by my original statements about the sound I heard.... but for different reasons. 
 
Turns out the HPA-1 had what I believe to be a counterfeit OPA627 in there, and the HPA-2 had the OPA2134. Not sure if you guys have tried OPA627 but the real version is pretty good - the fakes not as much. This version sounded warm, and pretty smooth, but lacked some detail on the top end, and had some kind of glaze on the midrange. In comparison the new model is a lot more clear and well rounded. These differences apply doubly so for the older USB section versus the new model. Due to the circumstances I can't really be sure how the stock HPA-2 amp section compares to the stock HPA-1 when both have OPA2134. I'd like to say it's improved but I can't be sure. 
 
Anyway, I have a few nice opamps such as Muses 01, Muses 02, LME49720, AD797, OPA1641.... I really wanted to roll a bunch of them but just ran out of time. The loaner is now on its way to Maxvla so maybe he can give that a try when he has a chance. 

 

[conquerator2]

So is it confirmed that the hpa2 has no gain setting at all? (either the usb or no usb version)?
What's the gain setting then and how would I drive many different headphone with one gain setting?
This seems like a really dumb thing to me from Matrix...

 

[Maxvla]

HPA-2 is fixed +15dB.