Nice! After tweaking the DefaultInputDevice and DefaultOutputDevice I get stable operation on MAudio Audiophile2496, Terratec EWS88D and the EchoAudio Layla24. All tested with a latency of 256 samples @ 44.1kHz under Win2k (in Standard PC mode, not ACPI).
Tonight I'll look at enabling multi-channel operation and try my RME Hammerfall DSP again.
thanks a lot!
Johannes