I just realized I forgot one. I sent my Optipus Compressor to
@scubaduba a while back for his thoughts and it had some issues largely associated with 6N21B tubes, so I'm skipping the 6N21B version of that and giving Optipus the X Series treatment as well. The main reason I forgot to mention this one before is that I already have the new boards designed for it and they're sitting on a shelf waiting to be put together and tested. I'll get it together after December has shipped and let everyone know how it goes.