Not true for vacuum tubes you get with stock amps are not verygood vs the originals from 1970 on down .the vacuum is of the gasses the inspection of the grids on average over 10 % variances inside gridsor more years ago 2-3% was common
the materials not even close maybe 3000 hours on average NOS tubes from the 50s many times 10,000 hours , some rectifiers run for10 years . Emissions labs in Europe are great as well as a few others for premium brands . Call vacuum tube services, or Brent Jesse recordings to get true New closely matched vacuum tubes a big upgrade in sound also..I grew up on all the classic tubes and the majority of Chinese, and Russia tubes are average at best compared.
the materials not even close maybe 3000 hours on average NOS tubes from the 50s many times 10,000 hours , some rectifiers run for10 years . Emissions labs in Europe are great as well as a few others for premium brands . Call vacuum tube services, or Brent Jesse recordings to get true New closely matched vacuum tubes a big upgrade in sound also..I grew up on all the classic tubes and the majority of Chinese, and Russia tubes are average at best compared.