Quote:

dlaloum said:

Thanks Purrin
 
I have an M-Stage with 3k9 class A adapter and OPA627's on Brown dog on the way - I assume the OPA627's will be top/bottom 
That will be the starting point of my listening (opa2134 stock, then OPA627 class A)
 
...
My grab bag will include (early next week when it all rocks up!)
 
OPA627
OPA637
AD797
AD744
LT1028
LME49860
OPA2107
OPA2111
OPA228
OPA49720
 
So this little exercise is likely to take some time...
 
Any experiences people have had with the above in the M-Stage and especially with the M-Stage and Class A mod very much appreciated
 
But as the saying goes " Nothing succeeds like excess, and nothing exceeds like success"

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You are welcome.  Beware OPA637 isn't unity gain stable and is prone to oscillate (do funny things).  Be sure to up the gain.  I liked OPA2111, but didn't explore it further once I got the LM4562.
 
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daisangen said:

I just replaced LM4562NA with a LME49720NA and it's definitely bassier than the LM4562NA. I know they are supposed to be identical, but there's no way in hell this is placebo. I tried going back to LM4562NA and yep, my findings still stand. Other than the bass amount, I think they sound very similar.

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There's conjecture that LM4562, LME49720, and LME49620 are all the same chip but binned like CPUs.  I have OPA2107s that sound very slightly different - same qualities but differing sound balance.  My LM4562 and LME49720 sound exactly the same.  It's a mystery to me.
 
On another note, now that I've sent a few of the class A adapters out to folks who've ask for them - and this is something I wanted to point out - but just forgot...
 
Pushing the op-amps into class A only works if you are feeding into a buffer with high input impedance. In the case of the M-Stage, the op-amp voltage gain section is feeding a diamond buffer / output stage. Please don't do this in CMOYs, DACs, etc. unless you know what you are doing.

Guys I am happy to reporrt the Matrix is stellar with the LCD2 and at o gain. It has tremendous basss slam and it presents all the details. It has worked on every headpone I have tried it with and performed well above the inexpensive cost factor.

Quote:

frank i said:

Guys I am happy to reporrt the Matrix is stellar with the LCD2 and at o gain. It has tremendous basss slam and it presents all the details. It has worked on every headpone I have tried it with and performed well above the inexpensive cost factor.

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How's it compared to the Decware? Different beasts, but I'm curious. I like the M-Stage so much that I'm debating whether to start mods on my Melos or get something else.

 
Quote:

purrin said:

Quote:

frank i said:

Guys I am happy to reporrt the Matrix is stellar with the LCD2 and at o gain. It has tremendous basss slam and it presents all the details. It has worked on every headpone I have tried it with and performed well above the inexpensive cost factor.

Click to expand...

How's it compared to the Decware? Different beasts, but I'm curious. I like the M-Stage so much that I'm debating whether to start mods on my Melos or get something else.

Click to expand...

The Decware is a great amp. I was concerned it would not handle the Planar but it makes them shine. The SSpresentation has much more bass slam. I like both amps but I lreally enjoy what tubes amps can do and the soundstage and vocal presentation that tubes bring but the Matrix performs well above what it cost and probably the best bargain to be found. Keeping both. When I wanna rock and get slam the Matrix is the ticket.

Thanks purrin,
 
when you talk about gain - I presume you are talking about the gain dip switches and not a circuit mod of some sort?
 
My Headphones are 600 ohm OEM Beyers - so I am likely to need one of the higher gain settings regardless... (I believe..)
 
Quote:

purrin said:

 

You are welcome.  Beware OPA637 isn't unity gain stable and is prone to oscillate (do funny things).  Be sure to up the gain.  I liked OPA2111, but didn't explore it further once I got the LM4562.
 

Click to expand...

Quote:

dlaloum said:

Thanks purrin,
 
when you talk about gain - I presume you are talking about the gain dip switches and not a circuit mod of some sort?
 
My Headphones are 600 ohm OEM Beyers - so I am likely to need one of the higher gain settings regardless... (I believe..)
 

Click to expand...

I have found that the 10 gain setting works best with bothh my T1 and 770 600 ohm cans, They sound good at that setting and using 0 gain on the LCD2 so Matrix is great for low and high impedance cans and 10 gain on the D7000
 

Thanks Frank
 
we were focused on the Non-Stock setup though - and the need for higher gain on some opamps to ensure stability..... 
 
But thanks for the input!
 
And given that you are a Beyer 600ohm user - have you experimented with opamps and class A? And what have you found works best with the Beyers?

Anyone care to explain the reasoning behind wanting to apply some gain to an opamp?  I have seen it in this thread mentioned many times and don't exactly know why it is true. 
 
I mean for the opamp itself and not the other uses of gain for headphones.

Does anyone have any experience with the matrix and the hd 650?

 
Quote:

svfoo123 said:

Does anyone have any experience with the matrix and the hd 650?

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I just got my HD650s a couple days ago.  They are still burning in as a matter of fact, but I've been doing quite a bit of listening.  It's a phenomenal combination.  I originally had it set to 10db, but thought 18 was better since there are times I like to "crank" it.  I don't know how the Senns sound with other equipment, but the matrix makes em scream!  The Senns are so seductive that I have a tendency to turn them up louder than I would my Grados...by a fair margin. 

 
 
 
Quote:

ninjikiran said:

Anyone care to explain the reasoning behind wanting to apply some gain to an opamp?  I have seen it in this thread mentioned many times and don't exactly know why it is true. 
 
I mean for the opamp itself and not the other uses of gain for headphones.

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Some opamps need some gain to be stable.  For example, the BB specsheet says OPA637 needs gain of 5.

Quote:

francisdemarte said:

Can you post some pictures of this mod when you get a chance?

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The WIMA MKP2s .1uF / 100V fit underneath.  I believe the Lovely Cube cap pins are perpendicular to how the pins are on the Matrix - slightly different PCB layout.
 

Trying to figure out where the M-Stage / Black Cube Linear sit in the Headmap firmament
 

1. Opamp based gain stage OPA2134 (3 level switchable gain)
2. Walt Jung Diamond Class A discrete Buffer
3. Robust / Clean Power supply

 
Unless I am much mistaken that is a full semi-technical description of the amp 
 
Looking out there at popular amps, this seems very very similar to some other popular amps... :
 
Headroom Desktop Amp/DAC

1. Opamp based gain stage OPA2134 Biased into class A using constant current source (3 level gain) - not clear whether this is CRD or full Cascode based - anyone know?
2.  Walt Jung Diamond Class A discrete buffer
3. Regulated PSU (quality?) - optional higher grade PSU

 
 
Could anyone chip in with other similar designs?
Can we fill out this family tree, and see what type of sounds the family tends to produce, and what headphones synergise best..?
This would also provide a type of guideline as to what mods would result in what sound...
 
The Headroom desktop has the opamps running in class A (which can be done on the M-Stage with the mods) - but the Headroom goes one step further and uses a "proper" constant current source. (so I am told)
 
Not sure on where the M-Stage, BCL, and 2x Headroom PSU's rank - concensus is that these can definitely improve the sound. 
 
The Headroom should (in straight amp mode) therefore sound similar to a Class A modded M-Stage (OPA2134 based) - is this the case? Does the theory/model hold up?
Anyone out there have both?
 
This would also be interesting in terms of showing how much (if any) difference could be achieved by going from the basic Class A mod to a full blown constant current source mod....
 
Has anyone tried the Class A mod using CRD's rather than resistors?

Quote:

purrin said:

Quote:

francisdemarte said:

Can you post some pictures of this mod when you get a chance?

Click to expand...

 

 
The WIMA MKP2s .1uF / 100V fit underneath.  I believe the Lovely Cube cap pins are perpendicular to how the pins are on the Matrix - slightly different PCB layout.
 

Click to expand...

Looks like the Lovely Cube has those caps in the same orientation:
 
\
 
Another thing I want to do is move the gain DIP switches from the bottom to the back of my case. I think they are SPST and I'd like to tie the 4 switches into 2 SPST switches, since I can't think of any reason why you'd ever want different gain settings on each channel.

Quote:

dlaloum said:

Trying to figure out where the M-Stage / Black Cube Linear sit in the Headmap firmament
 

1. Opamp based gain stage OPA2134 (3 level switchable gain)
2. Walt Jung Diamond Class A discrete Buffer
3. Robust / Clean Power supply

 
Unless I am much mistaken that is a full semi-technical description of the amp 
 
Looking out there at popular amps, this seems very very similar to some other popular amps... :
 
Headroom Desktop Amp/DAC

1. Opamp based gain stage OPA2134 Biased into class A using constant current source (3 level gain) - not clear whether this is CRD or full Cascode based - anyone know?
2.  Walt Jung Diamond Class A discrete buffer
3. Regulated PSU (quality?) - optional higher grade PSU

 
 
Could anyone chip in with other similar designs?
Can we fill out this family tree, and see what type of sounds the family tends to produce, and what headphones synergise best..?
This would also provide a type of guideline as to what mods would result in what sound...
 
The Headroom desktop has the opamps running in class A (which can be done on the M-Stage with the mods) - but the Headroom goes one step further and uses a "proper" constant current source. (so I am told)
 
Not sure on where the M-Stage, BCL, and 2x Headroom PSU's rank - concensus is that these can definitely improve the sound. 
 
The Headroom should (in straight amp mode) therefore sound similar to a Class A modded M-Stage (OPA2134 based) - is this the case? Does the theory/model hold up?
Anyone out there have both?
 
This would also be interesting in terms of showing how much (if any) difference could be achieved by going from the basic Class A mod to a full blown constant current source mod....
 
Has anyone tried the Class A mod using CRD's rather than resistors?

Click to expand...

 
M-Stage stage is also similar to PPA with 2 channels but with no constant current source on output, no class A biasing on opamp, and a few other things done differently - the power for each output transistor is fed by its own cap on M-Stage. Opamp gain stage + diamond output stage is ubiquitous. I had the HeadRoom Balanced with Home modules (OPA2134) and the HeadRoom sounded quite different (whether balanced or not balanced) than M-Stage. The HeadRoom sounded very very powerful, detailed, and crunchy, but too cool, edgy, and slightly clinical, which made it not play well with any my Grados - although it matched my D5000 and Darth Beyers very well. As some others have noted, the M-Stage is on the warm side (it's all relative anyways). The input caps and the big PS caps (4700uF and 470uF x 6 - two caps per component on each side of the rail) probably contribute to the warmness. I guess what I'm trying to say is that implementation of the topology rather than the topology itself is what will determine the sound. I jumped on the M-Stage because I figured I had some options if I wanted to tweak it; and if I broke it, I'd only be down $280.
 
As far as PSUs, I the M-Stage on board PSU is better than the HeadRoom/Astrodyne switched PS, but the special HeadRoom dedicated PS is way better (and costs way more too - although it does got a lot of outputs.)
 
Class A mod with CRDs is on my to-do list. But I'm pretty happy with my setup as it is.