ASIO401 is an open-source ASIO driver for the QA401 created by Etienne Dechamps. Aside from some input I had on how the QA401 wire protocols operate, the resulting ASIO driver is Etienne's own work. And it looks well thought out, smartly architected and well documented.
The Readme.md located on GitHub will walk you through the install and use process. Etienne has created a painless installer too, located here. For me, I ran the installer, fired up ARTA and it worked on first shot. It's also been confirmed on Matlab and REW. He's very active on his issues page, too.
If you've been wanting to use a high performance AD/DA on your favorite ASIO-enabled app, then ASIO401 and the QA401 just might scratch that itch!
Congrats and thank you for your work, Etienne!