Nagra HD PREAMP HV enables very flexible tube rolling. With its unique auto-bias, there are mind-boggling options to tinker the sound. I am currently trying out the Amperex pinched waist 6922/e88cc from 1957. These are with red tips (low noise), indicating a hand-picked selection that was intended for radar, medical equipment, etc. Other even more exotic specimens will follow in a few days… Yes, a guilty pleasure…
