As Satnutwillb said, some receivers have an RCA connector labeled
SPDIF, by which receivers can "pass thru" AC3 data to a converter or a receiver that decodes AC3. Other receivers have an optical output that does the same thing.
However this all assumes that your receiver is capable of passing thru the AC3 data. Some receivers have these outputs, but still do not pass thru the AC3 data, and still other receivers don't even have these digital audio outputs. From what I have been able to determine, I think that your Traxis receiver does NOT pass thru AC3 audio, and does not have the digital audio outputs, so I think you may be out of luck. Hopefully I've read the specs wrong.