6R4P (6Р4П) Pentode 1

All tube operating points below are by no means definitive good sound recipe for your particulate tube project. Lowest THD point is not necessary best sounding one and there is always some variance even in a NOS tube batch from the same manufacturer!  Below information is only useful as a general starting point and is ment to get you in a ballpark when no measurement equipment is available.

Lowest THD operating point spectrum

30mA, -6.1V BIAS, 245Va

Other operating points

20mA, -6.8V BIAS, 260Va
10mA, -8.9V BIAS, 270Va
5mA, -5.5V BIAS, 270Va

Traced plate curves


Quite linear pentode with OK spectrum but very microphonic.

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