JJ 300 B tubes or others ?

Charles and everyone,
Nice to have a clear consensus. I'm upgrading the rectifier and remaining signal tubes in my Kit 1. The 300 B's will be next. Nice to have a path mapped out.
Thanks again!
By the way, seems that Grant Fidelity is out of the tube business... at least I cannot find a link to tubes on their site. Happy to be corrected if I'm mistaken.

There is a hyperlink on the Grant Fidelity home page for tubes.

I believe that PartsConnexion is selling (perhaps bought) Grant Fidelity's stock of tubes. Their recent advertising is cut and pasted from Grant Fidelity. Or check w member Trelja; I believe he also sells the BTs.

Haven't heard the Black Treasures, but I am enjoying the Genelec Gold Lions in my Parallel SET mono's quite a bit.

I see that Parts Connexion has matched pairs of Black Treasure tubes advertised on Audiogon today: https://app.audiogon.com/listings/tubes-shuguang-black-treasure-300b-tubes-premium-gift-box-grade-a-6-month-warranty-mat-2015-10-17-accessories-l7l-5j7