Different last letters (suffix):
6K4P - 2 set,6K4P-V - 2 set,6K4P-EV - 2 set,6K4P-E - 3 set available.
Tube is tested with professional tube Tester L1-3.
Va = 250 V, Vf = 6.3 V, Rc = 68 Ohm.
la min/max acceptable value = (7 - 13) mA.
All tubes meet the minimum and/or from nominal to maximum parameters.
RUSSIAN TUBES – LAST LETTERS (suffix) MEANING:
V (B) or R (P) - Tubes of special, very high reliability, mechanical strength.
E - Long-life tubes with guaranteed life of more than 5,000 hours.
EV (EB) - Tubes of increased reliability, mechanical strength guaranteed life of more than 5,000 hours.
D (Д) - Extremely durable tubes with guaranteed life of more than 10,000 hours.
DR (ДР) - Tubes of special, very high reliability, mechanical strength, and guaranteed life of more than 10,000 hours.
I (И) - Tubes designed to operate in pulsed mode, characterized by increased emissivity of the cathode.
K - Tubes with high vibration resistance.
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