Rerurn to Romy the Cat's Site

Jessie, I have two comments/questions.

Are you sure that using the USB you do not use the sound card? I am a software guy not a hardware guy and with my limited understanding I presume that an application that reads a file must talk to so kind of driver to convert a stream into I2S bas interface. My players that I to play files do not talk I2S bas directly but use ether custom drivers, ether Windows driver or Windows Kernel Libraries. It wok be nice if a software output the I2S directly but I do not think it is the case, correct me if I am wrong. The I2S bas is way lower interface than a player might recognize and here is what the drivers come – drives are the soundcard, aren’t they? Sure, soundcard have also stages to buffer the AES interface and any DAC has a stage to receive AES. They are certainly needless element and could be illuminated by using I2S… Still, we do need some kind of “converter” from file player to I2S and this I presume what soundcard/driver does. The soundcard in thin case might be just a set of DDLs libraries I guess, with no actually soundcard-hardware involved.

The Cosecant DAC looks interesting. I never seen or heard it.

http://www.wavelengthaudio.com/Cosecant-det.html

A few things that juts comes to might mind regarding the Cosecant. Gordon says that it is a Passive Multibit DAC with a single Shinko Tantulum resistor “because only a resistor can be a linear device over the entire audio band”. Well, I presume it shell be a ladder of resistors for each bit but I would not argue on it. He can run bits around the same resistor I guess… what however is important is that in this configuration the stability of the resistor mush be immensely superb as the atomic participle of data is measured against the value of the resistor. None of the resistors are so stabile. Even if you go with Vishay 102 and have it with .0001% precession the temperature drift would offset the value of the resistor in time. As I understand the Cosecant DAC do not use any re-calibration concepts…

If I have this DAC I would probably step away from the parafeed idea. I never liked it as I never understood why we need a capacitor and transformer to couple. If you use already a cap then make it capacitor-coupled and it will be it. If you want to put a transformer in play then make is with gap - it is line lever and there is not a lot of power in there. So, if I have the DAC I would try to put my own large, gaped amorphous transformer instead of what Cosecant uses. I would be trying to make the transformer slight HF-challenged to deal with HF filtration after the DAC.  It might be interesting also to play also with the selection of the output tube…

Rerurn to Romy the Cat's Site