I got my M-stage last Wednesday.It says v2.1 on the board.It came along with a power cord and EU adapter.
I was pleased to see how well built it is.The blue operation led on the front panel is quite discrete when on and not as bright as many have complained.It seems that there has been some improvement.I have the AKG K701 which as you all know are quite power hungry despite their relatively low impedance.My Xonar STX head-amp is powerfull enough to drive them up to a deafening level but it lacks musicality and warmth,so I got a JDSLabs Cmoy v2.0.2 to give it a try.I must admit that it sounded unbelievably great.So musical,transparent,airy and warm like I had never heard before.My problem was that I couldn't raise the volume to an enjoyable level because of severe clipping.It was a matter of current rarther than voltage as I was using an external psu at 18V.Soldering a second TLE2426CPL virtual ground solved my problem and I managed to raise up the volume to an audibly acceptable level.Then,having read all of this thread plus the Headfonia review I decided to go for the Matrix being half the price of my initial pick,the Heed Canamp.
For the past 4 nights I have been listening to my favorite music(mostly jazz classical amd acoustic) playing 24-96/192 recordings ASIO Foobar >STX>Matrix>K701.Indeed it's a good amp and a real bargain for the money.I'm using the 10db gain and there is no backround hiss even when the knob reaches the 6 o'clock position.Music sounds quite clear and detailed.Highs come out clear yet not sibilant,Mids are a bit dark though and Lows well,I know it's the K701 but I was never a bass kick fan,so a 5db extra gain from the equilizer brings it in balance with the rest of the spectrum.It's not the bass quality,as it is nicely articulated and clear but the quantity and I know that it's the phones' blame.
To be honest,I expected a little more...It is not a complaint.I will say it again that it is a great amp for the money and I do know that many much more expensive gear sound worse.I should blame the Cmoy,for sounding as good as the Matrix at a cost of 4 times less!Amazing piece of equipment...
As far as cabling is concerned,using an Oehlbach NF1 showed no detectable improvement over the common 3.5mm-to-RCA IC provided with the Xonar.
Now, about op-amp rolling, the only alternative I had for the time being since my LM4562 order will be here in a couple of weeks,was to use the OPA2227 of the Cmoy.Comparing it to the OPA2134 was not an easy task as they don't seem to have any profound differences.The 2134 has a slightly deeper bass,warm but not so well bodied mids.The 2227 on the other hand is a little more trnsparent and clear and that helps the mids which stand out more.It's as if it shifts the frequency spectrum towards higher values and the sound becomes less dark at the expence of some sibilance though.Since AKGs are bitchy with bass,and using some help from the equilizer seems inevitable in most cases,I decided to go for the 2227,at least until 4562 arrives.I will let you know about it when I get it.