Recommended cabels

Alas, wire is not a tone control! Contrary to what the wire fanatics claim! I bought my first high end system in 1977 so I speak from experience. I have bought and tried plenty of wire since then. None of it mattered, regardless of price! Your Linn preamp and Bryston amp are certainly capable enough!You must realize that recording quality varies from awful to sublime! The search for better recordings is where it's at - not the futile merry-go-round of equipment purchases!

You spell it 'cabel'.

Dude. Spell check is built in to all browsers. This isn't 1997. 

Oh and: you admit to owning a 40 year amp? Might wanna start with that. 

Speakers are the major factor in sound quality. The Dynaudio's are only two-way stand-mount boxes with all the inherent limitations of such designs (bass extension/power handling). Large floor- standers like Revel's  and Devore's will give you much greater jump-factor without the need for a sub. I will always prefer floor-standers.

If anything that era of Bryston amps are known for being excessively bright and zingy on top! I have a 3B which is indeed too zingy! A modern Class D would be a better choice for the Dynaudio's.

I’m pretty sure Cardas is what you want. I’m guessing Clear Reflection would be your first best bet.

Your new speakers are going to be extracting a lot of treble and be more flat. The result will be you are hearing deficiencies in your older electronics. If upgrading to contemporary electronics, I would use interconnects and cables from Cardas, they are much warmer and forgiving in the less expensive levels and get more neutral at the higher levels… by design.