@output555 When you say passive tube stage do you mean a stage without gain? Those are called buffers and are really helpful if you need to drive long interconnects. The "solid state" function of the Freya+ is in fact a buffer and adds no gain. The "passive" mode does not have the buffer stage. As I mentioned earlier in the thread, I don't really consider it a real passive stage since there is still active circuitry involved. Maybe I'm a purist but I want my passive stages to be nothing but passive components like resisters or transformers.
If you search for tube buffers you will find a variety of products out there but you're right, the Frey+ is not one of them.