Isolation Transformer and Subpanel recommendations

There are many isolation transformers out there new and used. What are the best recommended 5kVA/other isolation transformers for high-end audio setups. I live in the US so I need one that would be configurable for 110/120V output. I intend to put this on my dedicated circuit after my main panel in the house. The dedicated circuit is high-quality and 20-amp/10-guage in nature; this circuit is 110/120V, not 220. I'm looking for any recommendations for units that run quiet and have high common-mode noise rejection.

Also looking for recommendations on good quality sub-panels.

Thank you in advance for the assistance!