Pair NOS RCA Red Base 5691 Preamp Driver Tubes, NEW Boxes, USA, Ex Sound, Performance 1950s/60s

Pair NOS Vintage RCA Red Base 5691(6SL7) preamp driver tubes, Military Spec, Black Plates, Double D Getters, 5 Support rods boxes, 1950s/60s, NEW. Revered for their excellent sound and performance, they sound superb. They are open, detailed, dynamic, involving, spacious, transparent, smooth and musical. Both tubes test new on my Calibrated B&K Mutual Conductance tube tester. Both tubes test over 940 on both sides of both tubes where 640 is minimum good. The shipping cost includes safe packing, insurance, prompt shipping and tracking number. Buy with confidence, see my feedback. Good Listening, SonnY :)