Originally Posted by teiki arii
Antoine my friend, who is an engineer in Audio Pro, exchanged all IC-OPAs by his class A AZP discret OPAs...
I mean he changed IC-OPAs for AZP OPAs at conversion I/V stage, Low-Pass filter stage, buffer stage and headphone output stage! Antoine had to upgrade just a little the Power Supply, had to fix bias conversion I/V on AZP OPAs and that's all. You can't imagine what benefits this upgrade had brought along, by an inextinguible margin as deep as Helm's Deep. It's fantastic! It outperforms the DAC with IC-OPAs! If I had to give a personal value, I would give 70/100 before upgrading and 88/100 after upgrading. The DAC is used in his symmetric version (with XLR outputs) in my full symmetric system.
I won't give you any review, the main reasons are because of my limited vocabulary (I'm a foreigner, don't forget it) and because I think reviews are a kind of lies. Anyway, I actually let you know that transformation is outstanding, extraordinary. I cannot find a single weakness in this upgrade. I confirm what I have already written: if you find some IC-OPA "highly regarded", I have not that skills to qualify nor to describe impressions that AZP OPA can offer you... It's amazing and yes, this DAC is fantastic with the proviso that you first, you change IC-OPA for real first class ones. I have to tell you that this OPA are not to be sold in anyway, because they are prototypes and Antoine doesn't want someone to practice reverse engineering. He wants to keep property on it. If I tell you that today, it is for several reasons: no matter you find a good USB cable nor you use SSD in your computer or anything. If you do not optimize the power supply nor you don't change IC-OPA for betters, whatever you have very nice cables or a very good system, your system should sound wrong, not bad I agree, but not according to my experience. That's the point.
I have never heard any DAC as good as this upgraded one, never forever... Is it possible that I can find a better one? For sure, but I could live with this one all my life without dropping it, because I do not feel the need to. Nevertheless, I know I will sell it one day, I am waiting for a new symmetric peamp/DAC made by Antoine in a few months (or years?).