Quote:
Originally Posted by Puma Cat
The 6H30 (aka known as 6N30, as the actual Cyrillic letter resembles both an "N" and an "H") are a Soviet military avionics tube and are extremely durable. They should be good for at least 10,000 hours or so.
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This is generally true for most all small signal tubes (12AX7, 6SN7, etc.).
The 'rule of thumb' for power tubes (EL34, 6550, KT88, etc.) is 2000hr.
Power tube life varies depending on the amp, as some are harder on the power tubes than others, being run at higher plate voltage, etc. I owned a pair of Cary monoblock SET amps that used a Russian military tube that would literally break (either the internals or the glass envelope would crack) after ~1000hr. At $150/per, they were expensive to keep running.
And, we all hear what we hear. For me, in McIntosh MC275 & MC75s the 'Winged C' 6550 was a terrific sounding tube. Sad they shut down the plant that made all 'Winged C' tubes.