This would be a universal type test pcb. The jumpers allow choice of BNC or XLR i/o. Use a ground plane, SMT parts, all traces treat as 50 ohm lines (there are calculators for this). The BNC and any coax cables should be 50 ohm as well.
If you don't have a good signal generator, use an AES signal. Then you could hook up a scope, or do a big long digital loopback test in a DAW, things should be bit for bit identical.
With a scope you could run differential by using two channels, or single ended, by adding a 50 ohm load to the other BNC.
With an eye diagram you can do a comparison and estimate jitter and error rate. One caveat though is that I've never done this in a home lab type environment. The equipment most of us use for home use may not be sufficient to detect minor differences.