Matrix-M Headphone amplifier. Excellent condition (rating 7/10 just to be conservative). Second owner. Flawless operationally.
There are OVER 300 PAGES of posts on HeadFi in discussion on this unit, so you know it’s something unusual? The person I bought it from was local and mighty upstanding fellow who was an engineering student.
The unit has DIP switches on bottom (sorry, forgot to take a picture) to set the gain independently for each channel. Useful if you are down on hearing in one ear, or to tune input sensitivity. Serves as a pre-amp as well, and sounds pretty good, but I used it only as a headphone amp. It is very well built.
I am not an expert on op amps. I listened to it as it now is configured, which is how I received it. Three other opamps are included for your rolling pleasure—but—I did not roll them.
Burr Brown OPA 2134PA
LT 1364
OPA 2107AP
Read the Amazon Reviews and Google this to see all the positive reviews—and those reviews were with the 2134PA module it ships with—I understand the OPA627 in there now brings it to significantly higher performance level. I sounded so good as I received it, I never had an urge to try the other opamps.
http://www.amazon.com/gp/offer-listing/B0056ER22E/ref=dp_olp_new?ie=UTF8&condition=new
http://www.head-fi.org/t/475618/matrix-m-stage-amp-review-simple-cheap-and-excellent
Comes in original box and packing, generic power cord, the three extra opamps. Will ship FedEx at buyers expense. See my extensive feedback on Agon, Ebay and HeadFi. See the links for more info.
This unit looks just like the ones in the pictures—except I believe this is a later version with enclosed power transformer to cut down further on noise (which there is none of—very quiet).
Thank you.