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Old 27th December 2015, 12:09 PM   #1
316a is offline 316a  England
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Default 4P1L vs 4P1S

I have some 4P1S tubes and got round to running some through the tester as triodes . Compared to 4P1L with -22V grid bias for approx. 35mA anode current ~5mA/V , with 4P1S I need to back off the bias to -27V to stay within dissipation limits and get around 4.2mA/V for a 35mA target current . Anyone running these filament bias are going to cook their 4P1S pretty quickly...

It almost seems as if these are different valves in terms of biasing which is hardly subtle . Has anyone got a (preferably translated) datasheet for the 4P1S or run any triode curves ?

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Old 27th December 2015, 12:28 PM   #2
316a is offline 316a  England
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Just opened a few from another batch and found a datasheet inside a box Oddly although appear to have been supplied to the Czech military by the Chinese , the datasheet is in English . Ties up with the operating point tables for the 4P1L

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Last edited by 316a; 27th December 2015 at 12:30 PM. Reason: addition
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