5691 RCA Red Base
The 5691 RCA Red Base is the Holy Grail of 6SL7 tube types. Built to last 10,000+ hours, this tube is rich and melodic with an overall smoothness that can't be beat. Take this chance to own the best 6SL7 variant on the planet. We have multiple brands on hand, but all are RCA *made* Red Base 5691.