Tube cross-reference
RS681 alternatives, equivalents, and replacements
Review exact electrical variations and directional substitutions recorded for the RS681 power - tetrode (not beam). Compare core specifications and verify every restriction before using a replacement.
No alternatives recorded
Tube Tinker does not currently have an exact variation or directional substitution recorded for RS681.
Verify before substituting
Matching a base or heater voltage is not enough to prove that two tubes are interchangeable. Check pin connections, heater current, maximum ratings, bias requirements, warm-up behavior, and the equipment manufacturer’s service documentation before making a substitution.
View the complete RS681 specifications →