Matrix M-Stage


New Head-Fier
Pros: Cheep in comparison with analogue amp...solid symply to upgrade
Cons: Power botton placed in the rear...
I useed my Matrix very rarely from 2 year to now because was too arsh for mee.
I prefer my little dot or lake people or my rega ear...but reading in internet the possibility of replace the amp chip for better resultI bought a normal LM4562NA Amplificateur Operationnel TEXAS INSTRUMENTS for 9€ shipment included. 3 minutes to replace the original one end NOW.....a miracle. Everything go right and musically correct. I tested wiyh my hd600 and HIFIman he400i .....supeb with the max gain to +12db.
The next day I'll try with my Grado sr325i and dt990 and dt880(600 Ohm)...I'll see!
The new burson SS v5i did wonders for my 2C. It was even better than the v6.
Pros: Great build and sound. Four different gain settings, easy to change op amps, great value
Cons: 5Ohms impedance is slightly high, slightly warm, physical deisgn may not appeal to everyone
The M-stage HPA-1 was purchased by me from an eBay seller about a year ago for $180 including a class A biased OPA627 op amp.
The HPA-1 was the first generation in the M-stage series and have since then been followed by the HPA-2 and the quite recently released HPA-3. The HPA-1 was released back in 2010 but I still think that it offers enough interesting features to be worthy of a review in 2016.
The HPA-1 came with one version without built in DAC (the one that I’ve got) and one with built in DAC. Both were available in black and silver so a total of four different offerings were available. To my understanding the original version with USB is no long available (but generation 2 and 3 is) while the pure amplifier version is.
The HPA-1 is still available from several sellers and here’s a link to the Amazon listing of it:
I’m not in any way affiliated with Matrix.
Short introduction to Matrix Electronic:
Matrix Electronic Technology Co. Ltd., located in Xi'an Economic and Technological Development Zone, is a high-tech enterprise that dedicates to the R&D, manufacture, marketing and sales of high-fidelity digital audio products. The company has its own digital audio brand; meanwhile, it also collaborates with a number of domestic and foreign companies on OEM and ODM business.
About me:
I’m a 43 year old music and sound lover that changed my focus from speakers to headphones and IEM’s about five years ago. At that time I realized that it wasn’t realistic for me to have all the different setups that I wanted and still house a family of four children and a wife so my interest turned first to full sized headphones and later also IEM’s.
My preferences are towards full sized open headphones and I believe that also says something about what kind of sound signature I prefer (large soundstage in all directions, balanced and organic sound).
My music preferences are pretty much all over the place (only excluding classical music, jazz and really heavy metal). My all-time favorite band is Depeche Mode although I also listen to a lot of grunge/indie, singer/songwriter/acoustical stuff as well as the typical top 40 music.
I do not use EQ, ever.
I’m a sucker for value for money on most things in life Head-Fi related stuff is no exception.
The Matrix M-stage HPA-1 is a solid state headphone amplifier.  
The HPA-1 is literally built as a tank. It’s made of metal and feels very reliable both in outer- and inner- design. It really feels like a non-nonsense product built to last for a long time.
The physical design of the HPA-1 (long in depth and short in width) is a not typical one and this may be a problem for people preferring to stack their gear.
The volume knob does also feel very solid and has a perfect amount of resistance when being moved to raise or lower the volume.
The HPA-1 offers two RCA inputs where you connect your sources and one RCA output for its pre-amp function. It also has a 6.3 mm jack to connect the headphones to.
To continue it also offers a switch to choose which of the line in sources to listen to and underneath it also has gain switches. The gain switch can be put to four different options: 0, 10, 18 and 20dB. I really like to have four gain options to choose from. This was the reason for me choosing the HPA-1 over the newer HPA-2 when I made my purchase. Finally there’s also an On/Off switch which, unfortunately, is placed on the back and makes it a bit hard to reach when placed in a rack.
Op amp socket with the Burson Audio SS V5 in place
Gain switch
Four different gain settings
Under the hood
With the lid in place
The back
The specs:
·         Output: discrete
·         Gain Switchable
·         Frequency Response: 10 Hz (-0.3dB) ~ 35kHz (-1dB)
·         Signal to Noise Ratio: >95dB (0dB)
·         Distortion: <0.001% (6 mW/300 Ohms)
·         Input Impedance: 47 kOhms
·         Output Impedance: Line-out 60 Ohms, Phone-out 5 Ohms
·         Output Power: 200 mW/300 Ohms, 400 mW/60 Ohms
·         Power Support: AC 220-240V/100-120V 
·         Front Panel Color: Black/Silver
·         Weight: 2 kg
·         Device Dimension: 280 x 110 x 42mm
I’ve used the M-stage on and off for the last year and it have played for well over 100 hours.  
I’ve fed it from my Advance Acoustic MDA503, the GO720 and the CEntrance DACport Slim and it has worked very well in all combinations.
Demo list:
Mark Knopfler – Sailing to Philadelphia
Røyksopp (Feat.Susanne Sundfør) – Save Me
Ane Brun – These Days
Michael Jackson – Dirty Diana
Metallica – Die Die My Darling
The Peter Malick Group – Immigrant
Eva Cassidy – Songbird
Thomas Dybdahl – A Lovestory
Norah Jones – Don’t Know Why
Celldweller – Unshakeable
Jack Johnson – Better Together
Seinabo Sey – Younger (Kygo remix)
Dire Straits- So Far Away
Bjørk - Moon
Lupe Fiasco - Deliver
Morrissey – Earth Is the Loneliest Planet
I’ve got to be honest and admit that I find it pretty difficult to describe the sound from an amplifier. To me the sound of headphones/IEM’s is more easy to describe than that of amplifiers and DAC’s. Because of this I’ll do a brief description of the overall sound from the HPA-1 and then compare it to a couple of other amplifiers to highlight the difference and similarities to them.
The first thing that I noticed when I started to listen to the M-stage was the black background. It was simply on another level than I’ve ever heard before. It sounds so calm and with great authority to everything it does. I don’t feel that it does not highlight any particular frequencies but the overall sound is full and slightly on the warm side. Although it doesn’t sound very vivid it doesn’t strike me as particularly laid back either, neutral with a warm tone would probably be the best way I can describe it. The extension in both ends is very good and I don’t think that anything is missing. Soundstage feels natural and separation is very good. While some amplifiers with wide soundstage can tend to sound slightly diffuse (combined with some headphones) I don’t find this to be the case at all with the HPA-1 and it’s very easy to hear the position of each instrument. I’d characterize the overall signature as full, distinct, slightly warm and with an excellent timbre to it. 
Op amp rolling:
The M-stage uses one dual op amp that’s mounted in a DIP8 socket and is very easily user replaceable. I general I find op amp changes to be quite subtle, especially when a/b testing with short listening sessions. I find that long time usage makes it easier to say at least which sound you prefer and which may cause more fatigue or other wanted/unwanted characteristics from the different op amps. Still I’d consider op amp changes fine tuning kind of in the same way as with tube changes. In short the Matrix M-stage will always sound like the Matrix M-stage but smaller adjustments are possible. I’d also like to say that there are no “better” or “worse” op amps in my opinion but there may be differences in synergy with the rest of your system and of course also in what preferences one have.
As I’ve already mentioned my HPA-1 came with the OPA627 pre-installed. Lately I’ve acquired a MUSES8820 op amp and Burson have been so kind to send me a sample of their Dual Supreme Sound (SS) V5 op amp for my shoot out. Big thanks to Dennis at Burson Audio for the support of my little project and for putting up with all of my questions.
For those interested in reading more about the latest generation of the Burson op amps (V5) here’s the link to their site with more information:
I've also posted a review for the Burson Audio SS V5 with more detailed information about it. Those who's interested can find it here:
On top OPA 627, below MUSES8820, on the right Burson Audio SS V5
Premium product in premium package
OPA627 (class A biased), $30:
With the OPA627 installed the warmth in the HPA-1 is easily noticeable but clarity and details are still in place. Focus on each instrument is excellent and the OPA 627 is the most intimate sounding among those tested here.
Full bodied, focused and warm is keywords for this op amp.
Burson Audio SS V5, $70:
With the SS V5 the black background of the HPA-1 is even more noticeable. There’s also more air to the presentation and the stage feels wider while still keeping the great positioning of each instrument. The more airy presentation also makes it feel less warm if that makes sense. The V5 has great extension in both ends.
Rich, detailed and airy is keywords for this op amp.  
Muses 8820, $13:
The MUSES8820 sits nicely in between the OPA 627 and SS V5 when it comes to warmth and soundstage. It has good extensions in both ends and is quite neutral.
Neutral and yet very musical is keywords for this op amp.
I’ve also made a short breakdown of the characteristic of the three op amps I’ve compared:
Warmth: 627 > 8820 > V5
Black background: V5 > 627 = 8820
Soundstage: V5 > 8820 > 627
Extension: V5 > 8820 > 627
Airy presentation: V5 > 8820 > 627
Separation: V5 > 8820 = 627
Once again these differences are not big but it’s how I hear them with my ears in my system. That being said it’s no doubt that I prefer the Burson offering over the others for long term listening.
The output impedance of the headphone out on the HPA-1 is rated to 5 ohms. This means that it may not be the ideal pairing with very easy to drive headphones and IEM’s. In theory it should be paired with headphones that has an impedance of 40Ohms or greater to perform its best.
The HPA-1 has plenty of power to drive all my full sized headphones, even my modded Fostex T50RP’s, which are the most demanding pairs I’ve got in terms of power, get more than enough power from the 10dB gain setting. The official power rating of the M-stage is 400 mW at 60 Ohms and 200 mW at 300Ohms so it should be enough for most headphones.
AKG Q701:
The combination of the HPA-1 and the Q’s are a match made in heaven in my opinion. The slight warmth and power from the M-stage really bring out the best from the Q’s. Bass is as impactful as I’ve ever heard with them and the overall presentation is very enjoyable. Also the great positioning and separation of the M-stage seem to work very well with the Q’s which can be a bit diffused with some sources in my opinion.
Grado SR325is:
Although the Grado’s only have an impedance of 32Ohms I find them to sound excellent combined with the M-stage. The slight warmth combined with the full and calm presentation seems to pair very well with the lively nature of the Grado’s giving them a very pleasant and enjoyable overall sound.
Philips Fidelio X2:
Although the X2’s certainly doesn’t sound bad with the M-stage it’s the only headphone that I enjoy even more with the Little Dot I+. I don’t know if it’s the 30Ohms impedance of the X2’s or the full and warm nature  of the HPA-1 that’s to blame but on some recordings the bass get slightly too much for my preference. After spending a lot of time (and money) on different tubes and op amps for the LD I+ to make them perfect for the X2’s I’ve settled on a combination of Siemens 6AK5W tubes and the MUSES8820 op amp that really bring the X2’s to the next level for me. The midrange is more forward and mid-bass slightly reduced compared to the HPA-1.
Please note that the comments in the comparison section are not in absolute terms but in comparison between subject A and B. This means (as an example) that if subject A is found to be brighter than subject B it does not necessarily mean that subject A is bright sounding in absolute terms. I hope this makes sense.
I this comparison both amplifiers were fed by the Advance Acoustic MDA503 DAC equipped with Ei NOS tubes in the output stage. I’ve been listening through my Philips Fidelio X2’s.
I used a simple Android app to volume match the amplifiers so although maybe not perfectly scientifically the result should still be pretty correct.
I used the M-stage with the Burson SS V5 installed when doing this section.
Little Dot I+ vs HPA-1:
The LD I+ ($140) is smaller than the HPA-1 and has a built in power supply solution just like the HPA-1.
As already mentioned I’ve settled on a Siemens/MUSES combo of tubes and op amp for the LD I+ and that’s what I’ve used it with in this comparison as well.
Being a tube/solid state hybrid the LD I+ introduce some noise with easy to drive IEM’s that makes it not match the HPA-1 in the level of black background. Compared to the M-stage the LD I+ have a more forward midrange and a very slightly less warm sound with a more lively presentation. The M-stage on the other hand feels more even across the frequencies and also slightly fuller and with more authority to the way it sounds.
The HPA-1 offers a bit higher power output (200 mW for the HPA-1 vs 150mW for the LD I+ at 300Ohms). The LD I+ also offers a gain switch for 3.25 or 6.5 dB compared to the HPA-1’s four different settings (0, 10, 18 and 20dB).  Unfortunately the output impedance of the LD I+ seem to be unknown except for the fact that it’s said to be made for low impedance headphones. The LD I+ has one pair of RCA inputs while the HPA-1 offers two and one set of outputs for pre-amp function. 
Schiit Magni vs HPA-1:
The Magni ($99) is much smaller than the HPA-1 and has a power supply solution that requires a wall wart in contrast to the built in power supply on the HPA-1.
Compare to the M-stage the Magni has an overall slightly thinner but also cleaner presentation. While the M-stage is slightly warmer than what I’d consider to be neutral the Magni is what I’d describe as spot on neutral. The result is a slightly more full sound most easily noticeable with male vocals and also more distinct character on the M-stage. The Magni can tend to sound a bit shouty (in comparison) with some music (Michael Jackson – Dirty Diana is a good example of this). They both offer similar great sense of space, separation and bass depth. The M-stage does have a more black background.
The Magni also offers a slightly higher power output (260mW at 300Ohms compared to 200mW for the HPA-1) but has no gain switch and its fixed gain is very high (making it more difficult to use with easy to drive IEM’s). The Magni has a very low output impedance (less than 0.1 Ohms) compared to the slightly high 5 Ohms for the HPA-1.  The Magni offers a pair of RCA inputs while the HPA-1 offers two and one set of outputs for pre-amp function.  
The Matrix M-stage HPA-1 may not be the latest addition to the amplifier market but it may very well be one of the best values with current prices.
The combination of four different gain options, pre amp function, two set of RCA inputs, easily user switchable op amps for fine tuning the sound and an excellent overall performance makes it a great option as long as you can live with an output impedance of 5Ohms.
In combination with the Burson SS V5 op amp it has become my favorite amplifier, especially when driving headphones that need a good amount of power to perform their best. 
This has been a project over several weeks and I've enjoyed every minute of it. Hopefully you've enjoyed reading it as well :wink:
Great review, thanks.
Inspired me to try roll op-amps on my HPA-3U.
Great and informative review Peter! I have the successor of your amp the HPA-2 classic and after reading so many interesting things about Op-amp rolling I decided to try it as well.
I wanted to ask you if you had any heat problems with your Burson V5 in your HPA, even after some hours? Does it still work flawlessly?
The reason why I'm asking is in the Gustard H10 thread many people who installed the V5 are having heat problems which caused some V5s to melt.
Now I am a little bit unsure if the V5 will work without heat problems in my HPA-2 classic or not
Hi Peter. I don't know if you are still monitoring your great review but, if you are, can you please tell me (as a total electronics novice) why there are two l.e.d.s in the circuit board...? I'm asking becUse I've recently acquired one of these little beauties (love it!) and noticed an orange glow inside... Why put LEDs in there...?!

YoYo JoKeR

100+ Head-Fier
Pros: Sheer Sound Quality, Immense Output Power, Excellent Features, Amazing Synergy with HD800 & K812
Cons: Inbuilt DAC

Me: I am an amateur musician & avid admirer of music from India. I would like to call myself a music enthusiast, rather than an audiophile. I was inspired by music since childhood, and as the time passed, the passion of music grew in me, and that subsequently led me to join Head-Fi. Eventually, I found the pleasure of listening to music mainly by the HD600 and recently, by the seductive LCD2 headphones, and realized the true components of recorded music. I usually like to listen to Indian Classical Music along with Bollywood songs. My main listening genres include classical, vocal, instrumental, jazz and sometimes pop.  With time, my sonic preferences have very much grown. I avidly admire transparency, accuracy along with neutrality, I mostly listen to full sized open back headphones and my all-time favorite headphones are Sennheiser HD800 & AKG K812, which I run from solid state amplifiers. I prefer & admire transparent solid state headphone amplifiers simply because they provide best possible accuracy, transparency & reliability.
I am an average consumer & a humble enthusiast, I like to pen down my thoughts, & I love to express my feelings. I do not receive for any sort financial benefits through this review. My articles are a purely honest writeup aimed for fellow enthusiasts here at Head-Fi community. My profound thanks to Matrix Audio for arranging a sample unit of HPA-3 for my evaluation.

Intro:  Matrix Electronic Technology Co. Ltd., located in Xi'an Economic and Technological Development Zone, in the ancient  city of Xian. Matrix is an enterprise that dedicates to development & manufacturing of high-fidelity audio products. It also collaborates with a number of domestic and foreign companies on OEM and ODM business. Matrix has its own highly qualified R&D team, which designs all of their products.
I assume we all heard of matrix only since its release of M-Stage headphone amplifer around 2010 which stirred the headphone amp market & was extremely well received across the world; hence It became a benchmark device. Im a proud owner of Matrix’s HPA-1 & HPA-2,  over more than two years. I loved them a lot, had a wonderful time with both of them. The M-Stage is getting updates in circuit board every two years. The latest model is HPA-3, improvised on previous designs.
HPA-1 was warmest & ‘richest’ sounding of all three, but had mediocre inbuilt DAC, plus slightly audible noise floor. It had the original BCL style gain switches. HPA-2 largely improvised from HPA-1, applied better performing 24/192 DAC with fixed +15dB gain. Also, the benchmark bass ‘bump’ has vastly reduced, with much better cleaner & flatter output.

Their latest release is HPA-3, successor to HPA-2. The HPA-3 has two variants, HPA-3U a Single end headphone amplifier with inbuilt DAC, whereas the  HPA-3B, truly balanced headphone amplifier without inbuilt DAC.
Technical specifications of HPA-3U:
Line Output
SNR: >-112dB at 20Hz-22kHz A-Weighting
THD+N: <0.0003% at 1kHz 1VRMS A-Weighting
Frequency Response: 20Hz-20kHz(+0.01dB/-0.04dB)
Output Impedance: 51ohms
Headphone Output
SNR: >-112dB A-Weighting
THD+N: <0.0003% at 33ohms 90mW 1kHz A-Weighting
Frequency Response: 20Hz-20kHz(+0.01dB/-0.04dB)
Output Impedance: 0.2ohms
Output Power: 2800mW at 33ohms / 420mW at 300ohms / 210mW at 600ohms at THD+N=0.01%
Gain:  5dB 10dB 20dB
USB Chip: XMOS U-Series Asynchronous USB Chip
D/A Chip: Texas Instruments DSD1793
SNR: >-110dB A-Weighting
THD+N: <0.002% at 1kHz A-Weighting
PCM Sample Rate: 16-24Bit /44.1kHz 48kHz 88.2kHz 96kHz 176.4kHz 192kHz
DSD Sample Rate: DSD64(DoP)
System Support
Windows XP/Vista/7/8/8.1 systems need to install the driver supplied
Mac OS X 10.6.4 and above version have native support and do not require a driver
Can be used with the most of Android devices via the OTG cable
Can be used with iOS devices via the Lightning to USB Camera Adapter
Supports both 110V & 230V (switchable)
Power Consumption: <25W
Fuse: AC250V/500mA 5×20mm
Weight: 1.7 KG

Packaging & Accessories: The HPA-3U comes packed in Matrix Audio’s strong cardboard box with foam protection inside & necessary accessories included in the package.
Included Accessories
User manual & Driver CD: Contains instruction about operating it & some warranty information. A compact disk containing HPA-3’s USB driver is included.
USB Cable: Good quality USB A-B cable. About a metre and half long.
Power Cable:  AC power cord to attach to mains supply.

Design and Build: The HPA-3U a marvelous & Robust build quality with perfect finishing. The case is redesigned from past to be more efficient.  More vents, thicker case, excellent finished edges & a modern look. It is made up of aluminium, and is painted in matt black & brush finished.  Overall the amp feels heavy in hand and comparatively longer is dimensions than other amps in size.  On the front side, we have Volume control knob, headphone jack is present in 6.5mm format along with a gain & input switch. On the rear side, we have Power socket cum switch, USB input port, along with a RCA input/output jack. Power button is very rugged & tough; Volume knob operates in a very smooth fashion & is very steady. Headphone socket is ball bearing type & goes easy on the headphone jack, does not cause scratches on the surface.
Special mention here is: HPA-3 is capable of handling both 110/220V, whose selection switch is on side of the amp. Plus the AC fuse is accessible right besides it. To remove the case & access the circuitry, one has to remove top four screws using allen keys Size (2 & 2.5) plus additional two side screws on each side, to remove the top cover. One small issue user might face here is: Vents on top cover can attract dust or incase a few water droplets fall down, it will straight on the circuit board & damage the board.
Considering the Internal components, HPA-3U has an entirely redesigned circuit board with has double sided PCB with no manual wirings except the toroidal transformer joints. Components are placed in a symmetrical & neat fashion.  All components used are carefully selected; including all dale resistors, Alps-27 blue velvet pot, premium caps. For D/A conversion, the HPA-3 employs DSD1793 (which is DSD capable version of PCM1793) for USB transfer, asynchronous 24 Bits/192 KHZ capable Xmos Chip. There are no user replaceable/serviceable parts inside theHPA-3U, except the op-amp scoket. Board is excellently soldered and has a reliable workmanship. TheHPA-3U generally runs warm by temperature due to being Class-A. It can also act as standalone headphone amplifier when fed with RCA inputs.

Sound:  The HPA-3U offers a very flat, detailed & accurate, sound  sonic presentation. Sound-stage width is superb & expansive. Overall puts up an amazing performance. Lows are tight, accurate & go deep with good impact, The ‘bump’ associated with older HPA’s is mostly gone. Mids sound very clear & open. Highs are very clean, airy, very detailed & extended. Overall no presence of any significant colouration.
I expected that matrix would develop and include a 32 bit DAC in their HPA-3U. The M-Stage have always been a strong & reliable amp, but contained a mediocre DAC. Though DAC in HPA-3U is good, but is not performing upto the standards of the amazing amp circuit. Soundstage in HPA-3U is just great . It has a fully circular 3D imaging. Detail retrieval, and dynamics are excellent, perhaps one of the best for an Amp/Dac under the price tag. Overall the sonic presentation is high level of transparency and accuracy.  Absolutely zero audible hiss/noise, and zero EMI pickup. Alps RK-27 pot does an amazing job of controlling volume very precisely without any channel imbalance & noise with retaining maximum sound quality. Another plus point here is, the HPA-3 has relay mechanism which prevent any noise pop’s when headphones are plugged in. This way, a better safety is guaranteed for the precious headphones.
Op-Amp: Stock op-amp is LME49860 from Texas Instruments, which does its job. To test if the HPA-3 scales with better op-amps, I tested it with many op-amps, and settled on LME49710HA X2 with browndog adapter. The HPA-3U indeed does scales well and supports the replacement op-amp. 
With LME49710HA, I have about 10% improvement from stock ones, with increased soundstage depth, excellent detailing & instrument separation & even more extension in treble. Overall increase in clarity & transparency.  For HPA-3U, ASIO suits better than other pluggins. Ofcourse it is audibly better than the default DS. In Matrix control panel, Set Transfer as “Most Safest” This again ensures maximum possible performance.
Driving Power: The HPA-3U is very powerful when it comes to driving headphones @2.8W power in tap. Drove my AKG K702 (which is a demanding headphone when it comes to ampling) well with 25% volume pot utilized in least gain of 5dB.  Infact, I couldn’t even switch over to 10dB gain switch, because the HPA-3U is so powerful, 5dB gain is more than enough to drive any headphones. I also tried my trusty LCD-2’s, U200 drove them very well, with good synergy. Both AKG K812 & HD800 sound fantastic HPA-3U.   It anything drives from IEM’s to planar magnetic with ease. Volume pot does a very good job here, volume increase very steady and in a highly accurate fashion. No channel imbalance. Overall, the HPA-3U impressed me a lot in the sound regard.

Comparison:  A very good competitor for HPA-3U we have here is Yulong Audio’s U200 whose review I wrote a while ago  which is also similarly priced & has similar functions. Now we have a tough competition, both newly released amp/dac’s, are priced around very well & both perform really well.
The HPA-3U has user-changeable gain 5/10/20X settings, & 230V/110V AC voltage switch to use in various parts of world without any hassle. It also has an internally swappable op-amp for any such rolling. Another advantage the HPA posses over U200 is that the HPA-3U has Alps blue velvet pot, which is simply well ahead of  Alps-16 used in the U200. The U200 offers WiFi module for an additional 100$, which I sometimes feel not very necessary. The Yulong U200’s gain is fixed, but it drives all earphones & headphones well.  AC voltage switch is not present, and can be a drawback for frequent international travellers. The HPA-3U also has mute relay mechanism, which is a plus for headphones safety.
In terms of build quality & workmanship, the U200 clearly has an upper hand with superior build inside & out, HPA-3U follows very closely, with slightly inferior part quality & design in few areas. The U200 has a very neutral & expansive sound quality with a touch of naturalness: sweet mids, slightly smooth highs & full bodied bass. Soundstage is deeper & more expansive in U200. HPA-3U has stronger bass  clear & open mids along with extended, & revealing highs, and not exactly ‘natural’ if I must say. I would rather call HPA-3U more analytic & clinical that the U200, but only with a slight margin. HPA-3 has about 15% lesser soundstage than U200, but has extended & more detailed top end. Mids are neutral compared to addictive smooth mids of U200. HPA-3U lacks soundstage perhaps due to lower 24/192 DAC capability. Audibly, The HPA-3 lacks the vast, airy & relaxed soundstage of U200, along with silky smooth mids. Top end is relaxed & airy in U200. The U200’s DAC is very superior & well performing, & has a fairly good amp section. The HPA-3U is just the opposite: superior amp section & fairly performing DAC unit.
In end of the day, both HPA-3U and U200 have an excellent performance & high value aspect associated with the price paid. Here the decision makes up of preferences only & sound quality almost same on both the devices. But HPA-3U has upper hand when it comes to flexibility & features.

Conclusion:  The HPA-3U continues the legacy & Reputation of M-Stage series forward.
The Matrix M-Stage HPA-3 is a benchmark & legendary headphone amplifier.  It is not just another amp, it has legacy behind it.  It impressed me not just in sound presentation, but I literally loved every inch of it. The HPA-3U excels in each and every criterion you put through it. Its workmanship is of high standards, and thus very reliable & robust in operation. The HPA-3U is reputed to have very good synergy & pairing with world famous high end headphones like HD800 & K812. I highly speak & recommend of the HPA-3U. It is a MUST HAVE device for HD800 & K812 headphones, & the pair  performs amazingly good with perfect synergy. Perhaps HPA-3U is the best solution for these headphones even at double the price.
1) Design and Build: The HPA-3U  has a very well designed and implemented build.  Both internal & external build quality is supreme excellent workmanship.
2) Sound quality: The sonic presentation here is very neutral & accurate & transparent, with minimum or none colouration. Sonically, performs extremely well.  Powerful enough to drive any dynamic  or even planar magnetic headphones.
3) Features: The HPA-3 has perfect set of features which are needed in a headphone amplifier device. Voltage switch, Alps Blue velvet, mute relays, op-amp rolling together makes it a perfect device.
Cons:  Inbuilt DAC: This has got be the only drawback for the HPA-3U. The inbuilt DAC is very good, but not in the long run. Audibly, I observed the inbuilt DAC is limiting the performance (particularly soundstage) of amp section.  I sincerely hoped, with HPA-3U, Matrix would bring a better performing 32 Bit capable DAC. This is the only area where I am disappointed with the HPA-3U.


Great review, thanks! I own the K812's and having read both of your reviews I'm still undecided whether to get the Yulong U200 or the HPA-3U (both are in the same price class in Europe, around €420).
is the line out in the back fixed or controlled by the volume knob?
I have the HPA-3U+ and the lineout is controlled by the volume knob. I found no difference if you have the volume set at about 75% - 80% from fixed ones. The lineout is also pretty good quality.


Pros: Fantastic sound quality! Very clean, detailed and balanced sound. Really strong power for high impedance headphones. Best buy until US 250,00.
Cons: None, really!
Fantastic sound quality! Very clean, detailed and balanced sound. Really strong power for high impedance headphones. Best buy until US 250,00..
It can drive easily my AKG K702 (famous for being hard to drive) and my SENNHEISER HD-650 (300 ohms). Multi gain level: +0db, +10db, +18db, +20db. It can drive every kind of headphone easily!
good review Johannus, I was really unimpressed. it has heaps of power like you said, very clean but quite dark imo. my ifi micro ican has much more detail than the matrix. that's just my opinion though.
Chris J
Chris J
Nice review!
With gain set to 18 dB, my M Stage never had any problems driving my 600 Ohm DT880 headphones.

Dave Popovich

New Head-Fier
Pros: Fantastic sound, unbelievably quiet noise floor, ultra low distortion
Cons: Possibly not enough gain for some high impedance headphones
If you're in the market for a high quality, reasonably priced, headphone amp, start with the Matrix M-Stage (and you may never need to go any farther). I recently (April 2014) visited the AXPONA audio expo in Chicago (what a great expo!), and auditioned numerous headphones, and headphone amps. One of my favorite headphone amps was the Woo Audio WA7 Firefly. But at around $1,000 it wasn't in my budget. Which brought me to the internet, in search of a stand alone, possibly Class A operation, headphone amp, with good reviews. Something that maybe sounded just as good, or close to, the Woo Audio Firefly, but at a lower price tag. I purchased the Matrix M-Stage, and love it to death. Let's face it, with audio gear, we all try to get as close to the music as possible (at least I do), be it in the studio, or a live performance. I am now much closer to the talent, when I listen to music on this headphone amp. Instruments and vocals just sound so clean, authentic, and close. Even though my current set of headphones are the SONY 7506, which have won my listening tests over and over, even with these headphones, it seems like the talent is right in the next room recording. This amp's noise floor (-95 dB) is super duper quiet too. Stereo tracking of channels is perfect. If you're comparing headphone amps, make sure you at least start with this one. It is worth every cent.           
Makiah S
Makiah S
Agree'd I owned and loved this amp for a good year, 


Headphoneus Supremus
Pros: Sound quality, relatively small size, value, pre-amp
Cons: Optional DAC
Greetings, this review will be a comparison between both generations of M-Stage amps with optional DACs. It will be copied and posted to both products. First the HPA-1:

Matrix M-Stage HPA-1 w/USB DAC

This is the original M-Stage based on the Lehmann Black Cube Linear. It is a far cheaper version while still using high quality internal parts, and shares most of the sonic attributes of the Lehmann. It's become a popular economic amplifier that works well with all headphones, and has synergies with certain headphones that make it punch well above it's price point. As this amplifier is designed to run high impedance loads this comes as no surprise that it would favor some headphones over others. The unusual thing is that even some low impedance headphones seem to work exceptionally well with this unit such as the AKG K701 (and its versions). One of the most surprising and compelling aspects of this amp is it's synergy with the Sennheiser HD800, a $1500 headphone. First, it is to be expected given the HD800 is a 300 ohm headphone, but it goes beyond this. Comparing the HD800 on other amplifiers, both solid state and tube, there seems to be no equal even at 2-3 times the price paid for the HPA-1. There are some that come close, equaling in some aspects, but changing the sound in a way unbecoming of an HD800, such as the Objective 2. The O2 is about half of the price of the M-Stage and does well with the HD800, but lacks in dynamic contrast, leading to a boring experience. There are surely many amps I've not heard with the HD800, but until you reach the $1000 mark, I've not heard an equal. At this $1000 mark we finally have competition with a tubed amplifier, the Decware CSP2+ (now retired) and jumping a little more to $1400, the Bryston BHA-1 again raises the bar slightly. So long as you use the M-Stage with widely recognized strongly synergizing headphones, the value is astounding.

The build quality is reasonable for it's price, but it doesn't feel expensive. It is solid, but it's clear this is an economical device. The stock knob is small and I was annoyed with it, so I switched it easily with a knob I found on eBay for a few dollars. The dip switches for gain are on the bottom of the unit, not an ideal location, but considering they won't be adjusted often, I will give it a pass. I eventually left them on +10dB, a setting that worked well with most of my headphones. One of the great things about this amp was that Matrix socketed the opamp, meaning it was easy for anyone without electronics experience to drop in a different opamp allowing them to slightly change the sound in a way similar to tube rolling. The stock opamp OPA2134 is a good average performer. With HD800s I prefer the LT1364, but have not done extensive comparisons with other opamps.

Where this amplifier with optional DAC falters is the DAC. As it was a $30 option, I won't be too critical of it, but suffice it to say that it is an emergency DAC only. It supports PCM up to 24/96kHz. Highs are etched, scratchy. Soundstage is compressed, lacking layers. Voices are rough and weakly formed. This is the DAC you only use when you have no alternative, but given it only cost you $30, it's hard to blame it too much. Now you may expect me to suggest avoiding the HPA-1 with the DAC, but you would be wrong. The difference between the HPA-1 and HPA-1 w/DAC is merely the loss of 1 of 2 sets of analog inputs (RCA). If you are only amplifying one source there is almost no reason to not get the optional DAC. You never know when you might need a DAC and the added cost is negligible. Sold your main DAC and are upgrading to a new one? Use this while your packages are being shipped.

Even with the optional DAC being poor, I still rate the HPA-1 w/USB DAC 5 stars due to it's total package value.

Matrix M-Stage HPA-2 w/USB DAC

Starting with the DNA from the HPA-1, the weaknesses that needed work, IMO, were the optional DAC, volume knob (bigger), and the front facia looked a little too 1990s. Matrix fixed two of these, leaving the one that is easily user-changeable. The front facia is no longer gold on black and there is a scoop where the LEDs, input select switch and headphone jack are located. The stock HPA-2 knob is an attractive silver thing that is slightly recessed into the face. It's a nice touch, but the part you hold is still small and harder to manipulate. I had an additional replacement knob from when I changed the HPA-1 so I fit it to the HPA-2 and I am happy. The HPA-1 with this knob had a slight gap between knob and face, but the HPA-2, with it's recess, has no gap there. The replacement knob I used does have a small ring gap around the circumference that I didn't like at first, but now I actually do like it. The hex screws were changed from 2.0mm to 2.5mm and from black to chrome giving the face some much needed contrast. With it's modern face, the non-audio updates were more or less complete. Another physical change concerns the sides of the unit. They are more attractive and are supposed to have increased cooling capacity. Something that may have been necessary due to the HPA-2 running noticeably hotter.

So far I've not gotten specs I can fully trust. For a long time the HPA-1 was listed as having a 5 ohm output impedance on it's headphone jack. When I got the HPA-2 I was told output impedance went from 15 to 10 ohms and that doing so has increased the power output. Power output for both units is still listed the same, however. I don't know what to believe.

One thing I can believe is the HPA-2s updated DAC is truly updated, and in a big way. This update comes in the form of a Burr Brown PCM1793 DAC chip giving us expanded sample rates up to 192kHz. What used to be an emergency-only DAC in the HPA-1 is now one of the best affordable DACs I've come across. Gone are the scratchy highs, non-existent soundstage and grainy voices. It's not all rosy, though. The soundstage is still somewhat compressed, but in a way a $500-1000 DAC would be. The highs still sound slightly artificial, but they are pleasant, not grating. Voices are smoother and more realistic. The optional DAC here is fantastic value. Combined with the already high value amplifier, this is now a usable all in one affordable solution for all headphones, especially the K701 and HD800 and others that share synergy with the M-Stage. This unit redefines my conception of an entry high quality headphone rig. Pair the HD800 ($1500) and the HPA-2 w/USB DAC ($320) and you have a $1820 rig that is hard to beat even with a budget of $3000-4000.

If you enjoy the sound of the HD800 and are planning upward moves for DAC and amp, I would highly suggest the HPA-2 as a stand-in while you save money or wait out production times as I have with my incoming Headamp GS-X mk2. I currently use the Matrix X-Sabre DAC into the HPA-2 which will be replaced by the GS-X when it arrives. The included DAC on the HPA-2 is surprisingly good and should not be underestimated, but compared to the X-Sabre it's no contest.

Try as I might, I never could seem to find reliable differences between the amp sections of the HPA-1 and HPA-2. There are probably some slight adjustments and perhaps improvements in parts quality, but the end result is too close to call. If you own an HPA-1 amp only, I don't see a compelling reason to upgrade to the HPA-2 amp only. If you are an HPA-1 user looking for a DAC but are tight on space, the HPA-2 with DAC gives you this in the same space.

Bringing up the rear are areas where I find the HPA-2 lacking. With the amp circuitry largely unchanged I didn't expect the buzzing with IEMs from the HPA-1 to go away, and indeed it didn't. Matrix has been clear about this amp being targeted towards high impedance headphones, though, so I will let this pass. The only other area of disappointment was the unexpected change to gain. The HPA-1 had dip switches allowing gains of +0dB, +10dB, +18dB, and +20dB. The HPA-2 no longer has the switches and the gain is fixed to +15dB. This shouldn't affect most headphones that are high impedance or are inefficient, but unlike the IEM buzzing issue, using even full size efficient headphones with the unit may be problematic due to reduced volume adjustment range. This makes the HPA-2 less versatile since it can't be used with as wide of an array of headphones as the HPA-1. Although I will dock it Design marks on this review, since it doesn't affect the majority of it's targeted headphones I will not remove stars or partial stars. A questionable design decision to be sure.

As I rate the original HPA-1 w/ USB DAC 5 stars, it's hardly surprising, after reading my HPA-2 comments, that the updated version is also 5 stars. The HPA-2 is clearly superior, but as the HPA-1 is being phased out I see no reason why the can't both be rated 5 stars.
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I also own the HD600 and it is a good match, though not as well matched as with HD800s. There are other combinations that likely do HD600s justice near the same price point.
I have received it and it sounds good together, but I think I like the Hybrid tube amp Fournier HTA 2 but they are still both very good amps. I absolutely love the sound of the HTA 2 but I do like the detail and sound stage of the M-stage. I wanted to ask if you could suggest opamp and bias mod with the HD600
Any idea how well it matches with low impedance (<=32 ohm) headphones? That output Z worries me but I really want to try my 10-II out of something with a high current swing without breaking the bank. 
I suppose I could just get an O2 for it in the event it doesn't match well but that's more money I don't have right now...


Previously known as muxamed.
Pros: Good power, able to drive almost anything, looks nice, built like a tank, price
Cons: It doesn't make coffee
I bought this amp after reading and asking on the Head-Fi threads. And I haven't regretted a bit. This is a well-made amp, looks nice, very discrete and drives my headphones (HD650, K701 and K501) without any problem at all. The high quality is evident in both the construction and in sound. It sounds clean and effortless no matter if I use my Senn cans or any of AKGs. It is more than worth it's price and there is no more to ask from an headphone amp.
I also happen to have the Senns HD 650 and AKG K702 (The same sounding as a 701 but with a removable cord)


Headphoneus Supremus
Pros: Almost everything
Cons: The iggy feet u loose a lot as they are badly glued!
As many said already before me...for the money u wont get better amp..and dont forget to do the class a opa627 opamp that gives him that extra! U wont regret when u buy this little even drove my he500 very well! But is best paired with a phone like the he300 or a my surprise it didnt do well with my iem the westone um3x
about the rude takato u know..this amp made me smile every time i listened to it..together with my he300..its a very neutral amp..mids are a bit edgy, the tremble is nice and soft...bass goes very low...but as i said..i used it with my he300..a dark sounding can...last sunday i was on a headfi meet where some people had grado's 325's and ssr 225's and one with a akg k702 and they loved the sound of my mstage (i sold it actually to a grado ssr225 owner the same day!)..and about my review about the he300 on which u, very respectfull (and to be honest ur right with that reaction on that that review!) as i just said..a k702 owner and some grado owners (225/325) loved the sound of my he300 more..they said it was fuller sounding, tremble was less dry then on the grado.and less bright...but grados are faster! the akg guy said he liked the soundstage on his akg more..and i agree with that...funny part is that i just sent my he300 to one of the grado 325 owners..he loved the sound so much he wanted to buy have it..sort of..a comparision..and am sorry if my reviews were a bit short..i just wanted to share my feelings and not witing down a cold review..
and about learning to type..maybe u have al the time in the world..i dont..i work..and i am not unrespectfull like u do..i wrote what i wrote as how i feel it..i can write a two page review here..but i didnt...seeing how u react ur maybe a bit to slow to check all the reviews all over the net and on headfi to know what i say is true about both..okay they are not perfect..but..for the price they are a steal!! oops...i apologize if i now sound a bit irritated...and as english is not my native language i probably wrote this down wrongly!..seriously..we are all here to enjoy music..some have long reviews..i am a bit short..but i damn know and believe in what i say...i wont say anything about things i dont own in contrary to some here on headfi!!!...i respect anyone here on long they respect me!
thanks friend


New Head-Fier
Pros: cheap, heavy build, looks expensive, sound
Cons: easy impulse buy
Wow so cheap so good.
Night Crawler
Night Crawler
Well, in all fairness, Jamesdeandoa did say easy impulse buy, and with a perfect 5 star rating in every category, I figured 10 just wouldn't cut it. Even bought 2 for the cat. :wink:
Nice detailed review!!! based on this detailed review im gonna buy one :p
once u get the mstage, the itch will start on the


Headphoneus Supremus
Pros: Great sound, low price, rollable opamps if you are into that sort of thing
Cons: None realy.... maybe the form factor, since it doesn't match other products so can't be stacked well?
That's a link to my full review, which has become a very long thread.
In summary:
The M-Stage is a clone of the Lehmann Audio Black Cube Linear, which is a high end headphone amp selling for around $1k. The M-Stage matches or exceeds the real thing in every aspect. It features a socketed opamp in the output stage so you can upgrade or try different things yourself (the Lehmann does not allow this). It is built like a tank, perhaps not the most pretty thing in your audio setup but it does have a certain utilitarian charm. At this moment I think this is one of the best choices out there for people to experience high end sound at a reasonable price.
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Do you still consider this a great amp for under the 300$ price point? and I am really interested in eventually getting a good quality solid state amplifier. I am currently using the Schiit Vali and my new favorite amp to go to when listening to the DT880s, they just work it together. I will be testing them  the HD600s when they arrive on Friday. Anyways, I am still looking for a solid state that can give me a bit of that wow factor with either of the headphones being used with the ss. So, if you could let me knwo and I would really appreciate  the advice and feedback


1000+ Head-Fier
Pros: Does what it needs to do effortlessly. Mult-Gain for different headphones. No hissing @ tuned volume.
Cons: Big bright shining blinding blue LED's .
WASAPI----->Bitmatched/Perfect transport----->Maverick D1 RCA SS output------>Matrix M-Stage(Stock)----->AKG K-702
I use these with my AKG K702 headphones and there really isn't much to say.  My previous amp had no problem powering these bad boys either but it hissed and popped at the volumes necessary to do so.  With the dip switch on the bottom controlling level of gain you can be assured it will power your most sensitive headphones equally to your power hungry hogs.
The volume knob is solid construction, and its potentiometer is completely linear.  Meaning you can fine tune to the perfect level of volume for detail extraction without killing your ears.  Case construction seems solid, though it does get hot which is probably due to the case  acting as a heat sink since it is after all a class A amp meaning it does get hot.  Nothing to be really worried about though.  I took half a star off for design only because the blue LED is the most blinding LED I have ever laid my eyes upon.  It is powerful enough to make my white shirt glow blue at night.
At higher than normal listening volumes with no music playing there was no noise or hiss on this unit through my headphones(silence).  At listening levels exceeding high and entering headphone damaging/ear damaging levels  there was a slight hiss.  But it is irrelevant considering at that volume you won't have the ears for headphones anyway.
Matching levels to my previous amp there are details that I can hear in some of my songs.  On the m-stage I confused them for static initially because I was not aware of their presence before.  When fine tuning my ears to comprehend was I was hearing it definitely was part of the song and not static.  Details that my other amp could not pickup at its maximum tolerable volume.  It also has a slightly higher level of clarity to every sound than my previous amp.  It is not a huge difference but it exist and is easily audible to the point that it was not placebo. (Previous amp was the HPA of the Maverick D1).
I gave it a 4/5 in Value because soon all in one units while slightly more expensive are able to handle multiple tasks.  Such as being a transport, a DAC and an HPA and doing all three proficiently.  But if you only need a stereo RCA headphone Amp for $250 you are getting something quite special.  It has changeable gain, and two inputs as well.  If can function as a pre-amp in the future as well.
I gave it a 4.5/5 for audio quality because while I feel it sounds perfect as is it is impossible to measure that since I have not owned enough equipment.
I gave it a 5 for overall quality because it performs as an amp should.  It is powerful, silent, and clean.
Overall its worth the $250-$290, definitely not something you will want to upgrade for a long time.  (Balanced inputs/headphone outputs? Ear Speakers?)
Edit: This review would probably make an English teacher cry.  I will come back and fix it up one day, wrote this while tired.