Welcome to the circle and thank you for owning our product!
Spark and Omega speakers are indeed a great combo. Come to think of it, that is not surprising as Louis and I have similar philosophy when it comes to designing audio products.
Spark can be used with a preamp. When the volume control is set to maximum, RCA inputs are directly connected to the amplification stage. As the volume potentiometer is in the rear of the unit there are no unnecessary wires. Even though maxing volume control is a perfectly good way to use Spark as a power amp, I find myself often setting it a 3:30 or 4PM position, i seem to like that setting most when using Spark with a preamp. What I’m trying to say is - experimenting is always good

Looking forward to hearing about your experience.
Enjoy,
Boris