Are any folks familiar with these tubes. Mine have whit printing that says "6BQ5/EL84..... Tesla/JJ". I am not seeing any similar images on the internet. I have 7 of these but need two quads. Is it worth searching for a couple more, or are they nothing special? Right now I'm using Genelex Gold Lions in my VTL Tiny Triode EL84 monoblocks. TIA!