I don't know if this matters to you. The Jolida JD-502P can use Tung Sol KT-120 tubes with no issue whatsoever. I don't know if the PrimaLuna Prologue5 can. I own the JD-502P and I really enjoy the amp immensely. I haven't heard the PrimuLuna amp but the people I've spoken too about PrimaLuna gear speak highly of them as well.