SPDIF or AES/Ebu interface

[Michael Buchstaller]

>However, what I am woundering is really what the point is here... are you
>really using tubes as the fundament switches of the D/A ladder?

Yes, i do. a simple gain stage, followed by a cathode follower to make sure
that loading from the R/2R chain will not alter the voltage coming from the
1st stage.

>I'm not a tube-head, but how well can one calibrate them as stable switchable
>voltage or current sources? As you go for more bits this will become more and
>more important since it causes distorsion, and not the kind of distorsion that
>you are looking for.

As i have seen with the 8 bits variant, i did not calibrate anything and it worked
surprisingly well.
In this project, i am not looking into real distortion. But i have built some tube amps
so far, and i feel it as a challenge to eventually build an all-tube digital amp.
(excluded the SPDIF interface chip and some glue logic) No semiconductors
anywhere in the audio path !

honestly, i do not know if it will make really an audible difference to commercial
converters, but i just want to do it !

>Anyway, if this is what you are intending to do it certainly sounds like a
>odd-ball project. It would be interesting to see how it turns out. Personally
>I would stick with a commercial linear DAC.

If more people are interested, i could make a simple web page with photos
and schematics.

>Well, I would be looking at the Crystal Semiconductor ones to start with.

I will be looking at their web site. Hopefully someone will sell me single parts.


-Michael Buchstaller