Rega Isis cd player ......Dedicated 20 amp circuit?

For $10K it probably has a good size power supply to feed the tubes. If I paid that much for a CD player, I would consider a separate 20 amp circuit for it, even if it was  across the house from the breaker box. I see no downside.

As far as I know, from the installation cost perspective, there's no difference between running a dedicated 20 amp line and a 15 amp line from the breaker box. It just gives you the option to use the wall plug in the future for a high current amp.