Some possible factors which come to mind:
-- The fact that environmental specifications (temperature, vibration, etc.) for operational conditions are more extreme than for their commercial counterparts, likely means that in a living room environment tube parameters are likely to fall within a more narrow range.
-- More stringent quality control, meaning that marginal tubes are more likely to be rejected.
-- Tighter manufacturing tolerances.
-- More stringent MTBF (mean time between failure) specs, and more stringent test and/or analysis requirements to verify MTBF, perhaps influence selection of materials so as to reduce burn-in and aging effects.
-- Burn-in requirements during manufacturing test reducing or eliminating the need for burn-in by the consumer.
Regards,
-- Al
-- The fact that environmental specifications (temperature, vibration, etc.) for operational conditions are more extreme than for their commercial counterparts, likely means that in a living room environment tube parameters are likely to fall within a more narrow range.
-- More stringent quality control, meaning that marginal tubes are more likely to be rejected.
-- Tighter manufacturing tolerances.
-- More stringent MTBF (mean time between failure) specs, and more stringent test and/or analysis requirements to verify MTBF, perhaps influence selection of materials so as to reduce burn-in and aging effects.
-- Burn-in requirements during manufacturing test reducing or eliminating the need for burn-in by the consumer.
Regards,
-- Al