35W4(1), 12BE6(1), 12BA6(1), 12AT6/12AV6(1), 50CS(1). Power output tubes are first mounted in test fixtures and burned in for 24 hours. This burn-in helps stabilize the internal operating parameters of the tubes before measurements begin. Each power tube is then tested and graded for technical characteristics specified by platinum tubes engineers.Tubes not meeting these criteria are rejected to the supplier or disposed of. Average tube life will depend on several parameters: product type, how the product is installed, loudspeaker efficiency, room size and acoustic damping, listening habits or average sound pressure levels, A. Line stability and purity, and other circumstances. Generally, preamplifier tubes last up to 5,000 hours, while power amplifier output tubes will last up to 3,000 hours. Near the end of their useful sonic life, aging vacuum tubes may degrade the sonic character of the product(s) they are used in.
The sound may become somewhat dry and lifeless, with a noticeable decrease in harmonic richness or bloom. Bass response may be diminished, and musical dynamics may flatten out or compress. Toward the very end of their service life, tubes may become noisy, noticeable as a slight rushing sound or rustling noise. It is far better to replace vacuum tubes prior to the end of their service life, before severe sonic degradation or outright failure occurs. Running vacuum tubes into failure may damage to other internal components and cause needless repair expense.Factors which can shorten tube life include inadequate ventilation, overdriving loudspeakers at continuously high volume levels, severely fluctuating A. Sagging line voltage during summer peaks of air-conditioning demand, or severe interference pulses or electromagnetic interference. The item "Vintage 1950's Zenith High Fidelity AM/FM/FMC Tube Radio S-46351 Working" is in sale since Saturday, September 23, 2017. This item is in the category "Consumer Electronics\Vintage Electronics\Vintage Audio & Video\Vintage Parts & Accessories\Vintage Tubes & Tube Sockets". The seller is "platinum_tubes" and is located in Canoga Park, California. This item can be shipped worldwide.