SOLD -These are the pre blue bottle tubes, but still cost the same. A significant upgrade to the stock El 34 tubes found on the AVA Ultravalve. I estimate about 900 hours on the tubes and it took about 200 hours to reach full break-in. Sophia Electric told me that the EL34-ST tubes are rated to have a mean life span of 7,000 hours, with a range of 5,000 – 10,000 hours, which translates to about a four to eight-year lifespan, with a median of just under a six-year lifespan, assuming about 1,200 hours per year of operation. So, plenty of life left in these babies. Price includes shipping and PP to lower 48 states. SOLD
