dsf to wav : what CPU power ?

[simoncn]

The control point decides on the format based on compatibility information that is sent by the renderer to the control point. BubbleUPnP and the Linn DS implement this renderer protocol correctly. You would need to check whether or not Sonore and PS Audio do this. The name of the relevant API is GetProtocolInfo.

If this support is confirmed, you could use the second of your suggestions:

dsf:-/wav24;176
for my Sonore and Akurate

This would play DSF files transcoded to wav24;176 on the PS Audio (better than not playing them at all).