Prefered 300B tubes for Canary Amplifiers

Typically, 300B XLS tubes can take a higher bias current, therefore, producing higher plate dissipation. 300B XLS tubes are drop in replacements for regular 300B, but their benefits are only truly realized if you amp has adjustable bias. I have had excellent results with Emission Labs 300B XLS tubes.

Why don't you contact Canary Audio with your question?

I do not know how many tubes that you would require or your budget or how you define "premium." However, in my experience in my 300b SET, the best tubes are the Takatsuki TA-300b followed by the Sophia Royal Princess. Both easily best the Shuguang Black Treasures. I have not heard the "standard" Psvane or the Psvane WE Tribute or any of the EMLs or any of the less expensive Sophias.

( http://www.westernelectric.com/products/300b.html )