Can anyone recommend a new or NOS 300B or 805 vacuum tube?

I had a friend test the amp and it is indeed fried. I will not be fixing it, nor will I get tubes for it. It looks as if something happened to the 805 vacuum tube socket. It is damaged.

If you don't want Chinese then there are the European companies like JJ, Sovtek, Gold Lion ...

Linlai  makes good tubes at reasonable prices! Don't fall for the belief that only premium priced tubes will do.

Most of the 805 amps with 300b drivers that I've seen are mass produced Chinese amps and these tubes rival the price of the amp.

OP, what price range are you shopping in?

Jerry