Pinnacle tubes,are they good?6SN7GT good or bad,made by them or rebranded?

Hello to all forum members. As usual I think this is the right place to ask this question.
Are Pinnacle tubes good? Did they make their own tubes or they outsourced them and rebranded them?
I've seen some inexpensive NOS Pinnacle 6SN7GT tubes on an on line shop from the UK and I wonder if these are good or bad.
I'd use them on a Yaqin SD-CD3 "tube buffer" (in conjunction with a Topping D30 D/A converter, I get a nice sound from this combination) which works on a cathode follower configuration. On it the quality of tubes make a difference but a subtle one.
Are Pinnacle 6SN7GT (no A or B) good or at least acceptable?
Thanksin advance for your replies.

 

Pinnacle tubes I used were made by Brimar. I have not used Pinnacle 6SN7.