B438 ~ W410. Tube Type: B438 – Directly-Heated RF / IF Triode. Replaceable with slight differences: 2-438, R62, W420, M350S, M504 (among others). A UX4-base version of the B438 also exists. Confirm before any substitution.
B438 ~ W410. Tube Type: B438 – Directly-Heated RF / IF Triode. Replaceable with slight differences: 2-438, R62, W420, M350S, M504 (among others). A UX4-base version of the B438 also exists. Confirm before any substitution.