Blue Jeans Cable Sound Good???

Without listening to the cable, is there any way to make a good choice of which cables to purchase, like amp power, receiver and speakers on regards to ohms, speakers etc...

Yes, IF you know all component factors regarding impedance, both in and out, frequency and dynamic response, of all components and cables, have a good mapping of the room, know what is wrong, have a trained ear and experience tuning systems and rooms. Being good at math also helps <vbg>

Pretty much skotches all advice here, online and most audio shops.

P.S. BJC make a good product. If you are using balanced XLR with out screen lifted at destination end, shame on you. It could account for the grunge.

For your configuration, assuming the amp is a balanced input, you should be using a twin or star-quad cable.

At the RCA, screen and -ve connection are to RCA Gnd
At the XLR, pin 1 should not be connected to screen

If using twin or star-quad cables, RCA connectors should only have the screen connected at the destination end.

@teo_audio -
coax is not used for balanced connections. Shield and ground are not the same. In balanced connections one rarely wants ground and shield connected. see https://en.wikipedia.org/wiki/Balanced_audio

@djones51 -
the cable in the speaker comprises part of the load seen by the amplifier. If you change it, you may change the sound of the speaker.

Voice coil wire is very thin, perhaps 40ga or smaller. Using your logic, the 12ga is over kill.

Speaker wire reacts to the amplifier and with the loudspeaker. Just as one may change capacitors from electrolytic to mylar to polypropylene to PTFE to PIO and detect no, some or great change, so to will changing speaker cables affect no, some or great change depending on the amplifier and loudspeaker. Similarly for TT/CD/DAC->Pre and Pre->Power connections.

The messy bit is that cables must be judged in a system and there is no guaranteed magic bullet.

@djones51 -

I fail to see how anything more than a basic 12 guage speaker wire which the manufacturer recommends is going to matter

There are many ways to arrive @ 12ga, any of which may sound different or not depending on amplifier and loudspeaker.

read http://ielogical.com/Audio/CableSnakeOil.php paying attention to how various cable geometries interact with the same amp and loudspeaker topology.

CAT cables are balanced end to end. The patch panel is grounded, but the cable shield is not connected at the source / destination equipment end.

When the screen is connected at one end only in twin or star-quad, it functions as an electrostatic shield and does not carry any signal current. A typical RCA coax carries current in the shield - not a good idea.

Lots of audio gear is badly grounded. Manufacturers add 3 prong power to unbalanced equipment 0v and presto, ground loop.

@ teo_audio

Most recording studios are wired as I explained. 
Isolated ground receptacles with earth home run to central star.
Grounds are never connected to shield - nor should they ever be.

Screen will do nothing for hum - except introduce it by creating a loop.

There is nothing unusual about having interconnects mixed with power cords. Almost every system on the planet operates thus. Running power and signal cables at right angles will do wonders for hum reduction.

I find it interesting that Teo cables are directional. Since conductors are liquid, and by definition liquids are in constant molecular motion, how in blazes can they be directional? Answer not required!