I’ve never been particularly impressed with RCA Phono connections.
High quality, tightly toleranced RCA plugs can be bought but they tend to be very expensive and to get the full benefit you need sockets to match.

Most reasonably priced RCA plugs only exert any pressure at their contact points because the centre pin and ground surround grip are not concentric to each other.

I’ve been using these for a while where changing to XLR has not been an option because of space consideration or expense.

http://www.thatcable.com/acatalog/in...onnectors.html

These have a split centre pin and unlike many that look as if the outer body will screw up far enough to exert pressure on the outer ring contact, these actually work. In fact, you have to back the body off a bit to get them on!

They will as standard just take a 6mm cable but if you use a tapered reamer on the back of the main body they will open up to 7mm.
A bit of care is needed when dressing heavy braid shield to make balanced or semi balanced leads; I’ve found un-plaiting the braid and separating into two strands that run inside the cable grip and then back over the inner shoulder of the grip and soldered on the outside works well also giving extra strain relief properties from the braid taking the strain.

Imo at this price they’re a steal