Tube cross-reference
DF668 alternatives, equivalents, and replacements
Review exact electrical variations and directional substitutions recorded for the DF668 voltage pentode - sharp cutoff (single). Compare core specifications and verify every restriction before using a replacement.
Replacement tubes for DF668
The following tubes are recorded as possible replacements for DF668. This direction does not establish that DF668 can replace them.
Voltage Pentode or Tetrode (under 100V)
The database records 1AD4 as a possible replacement forDF668.
No special restrictions are recorded for this substitution.
| Specification | Original tube | Replacement |
|---|---|---|
| Tube type | Voltage Pentode - Sharp Cutoff (single) | Voltage Pentode or Tetrode (under 100V) |
| Construction | Pentode | Pentode |
| Base | Not recorded | 1AD4 |
| Socket | WIRE8 | SUBMINIATURE7 |
| Base pins | 8 | 7 |
| Sections | 1 | 1 |
| Heater voltage | 1.25 V | 1.25 V |
| Heater current | 0.1 A | 0.1 A |
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 DF668 specifications →