Maybe I can add some information regarding the upgrade option. I did allready post this also here:
http://www.head-fi.org/t/557892/new-meier-audio-headphone-amp-corda-classic/375#post_11757756
Several weeks ago Jan Meier stopped by at my home. Over the years our relation has grown from headphone addict to developer to a friendship. So when Jan is on his way from Erlangen (Germany) to the Netherlands, he sometimes stops by for some hours which we truly enjoy. Sometimes he has some luggage with him like new developments he is working on. So one of the last times he brought his DAC and his Corda Classic with him and we fed it with the digital output out of my Audionet CD player. He told me that with one of the switches I could listen in to a new circuit. This new circuit, now called frequency adaptive feedback, was build in the DAC and in the Corda Classic. So with one switch I could change between old and new circuit in the DAC and with another switch in the Corda Classic.
Interestingly Jan did not tell me which switch did what or what too expect, so listening in the two devices was completely blind. I took my Sennheiser HD 800's and listend with my favorite music for testing audio equipment: Chesky Ultlimate Demonstration Disc, Youngblood Brass Band - center level roar, Bach Goldberg-Variationen Bwv 988 for violine (Mischa Maisky, Julian Rachlin, Imai Nobuko89) and David Munyon "Four wild horses".
After going back and forth I found that one of the switch positions was much better. I had no chance to discuss this with Jan during the 1.5 hour I was testing, since he was hanging out with my family and I was alone.
The difference was very clear and very audible.
While I tested between the headphone amp and the DAC I found that the difference was stronger for the amp and while still clearly better, less extreme for the DAC. As Jan explained to me later the DAC has less amplification stages and therefore the effect overall is smaller.
I have owned a lot of gear and still own some, like for example amps like the CEC HD53N, the Lehmann Linear with SSC feet and a Music Hi-Fi tube amp. But I was surprised that I have not heard some of the songs in that quality.
There where two distinct moments where I was surprised listening in my music.
1. At the beginning of the center level roar CD of the Youngblood Brass Band, in the intro "To Come Together" there is a rap with only some brass and a drum. The rap is recorded comparably quietly and you should not turn the volume up too much, since you would get a shock when the the second song starts with full force. Exact position of the rapper and size of the person were always a bit unclear. With the new circuit, it was suddenly so clear where he stood. He also wasn't just a voice but he kind of became a person.
2. At the beginning of David Munyon's "Four Wild Horses" there is something like a dark sound of a gong (I believe). While the sound is and was mysterious I never had heard so much from it. It became with the new circuit clearer and more tangible.
These are two examples out of many, where it was immediately clear Jan had improved something dramatical. Overall I had the feeling like the fog had lifted.
While listening I started to become unsure why my music sounded so much better. Did I just had a golden ear day? Was it different since I listened to my music at a normal volume while I usualy listen to my music at very low volumes during night time.
So I turned on my Music Hi-Fi amp (which I was using for the last year) and fed it with the analog signal from my Audionet Art G2 CD-player (https://translate.google.de/translate?sl=de&tl=en&u=http%3A//www.audio.de/testbericht/audionet-art-g2-328714.html). What a shock. I couldn't believe how bad it sounded in direct comparison. It was like going back a lot. And believe me, I have owned so many configurations and was thinking I had reached my audio heaven, which is the reason I am not so active any longer in the forum world.
Anyhow, I asked Jan if he could build this "modification" into his DAC and amp and sell me one and he agreed. So now the Jan Meier dream team is working in my home and I am very happy with it.
Two surprises I had since I own the configuration:
Although Jan does not advertise it, you can use the DAC with the iPad together with the Apple camera kit. I am even not sure if he was aware of it.
2. While I buy some high-res stuff myself, I was surprised how great my Qobuz MP3 320 kbps streaming sounds no matter if I use my laptop or my iPad.
So overall, I am surprised what a difference this new frequency adaptive feedback makes and I can fully recommend this new amp.
