So, having the afternoon off from work I got down to some testing.
I noticed that although there was a teredak device it was in fact using the standard windows driver. I was able to upgrade the driver to the teredak.
Asio worked as before seemingly ignoring the various settings and only working to the setting set in the control panel app. Irrespective of what was played everything was upscaled to 24/192.
Wasapi was a disaster, not even allowing 16/44.1 to play, giving instead the usual your hardware doesn't support the chosen format error. I did try the 24/32 bit switch but it had no effect.
However, and in frustration, I tried kernel streaming. This worked with the dac recognizing changes to sample rates.
On the face of it ive got a solution. Why I've no idea. Why kernel streaming should work on a win 7 machine yet nether asio of did is beyond me. Now whether the SQ is any different is another matter.
And of course it only worked today. It might not tomorrow!
Matt, any comment kernel vs asio or wasapi?