Tube cross-reference
21A6 alternatives, equivalents, and replacements
Review exact electrical variations and directional substitutions recorded for the 21A6 power - tv horizontal output (sweep). Compare core specifications and verify every restriction before using a replacement.
Exact variations of 21A6
These designations belong to the same electrical variation group. Their names may differ because of international standards, manufacturing tolerances, or materials, but they are recorded as electrically equivalent—not merely substitutes.
Replacement tubes for 21A6
The following tubes are recorded as possible replacements for 21A6. This direction does not establish that 21A6 can replace them.
Power - TV Horizontal Output (sweep)
The database records N339 as a possible replacement for21A6.
No special restrictions are recorded for this substitution.
| Specification | Original tube | Replacement |
|---|---|---|
| Tube type | Power - TV Horizontal Output (sweep) | Power - TV Horizontal Output (sweep) |
| Construction | Pentode | Pentode |
| Base | 9AS | Not recorded |
| Socket | B9A | B9A |
| Base pins | 9 | 9 |
| Sections | 1 | 1 |
| Heater voltage | 21 V | 20 V |
| Heater current | 0.3 A | 0.3 A |
Power - TV Horizontal Output (sweep)
The database records PL81 as a possible replacement for21A6.
No special restrictions are recorded for this substitution.
| Specification | Original tube | Replacement |
|---|---|---|
| Tube type | Power - TV Horizontal Output (sweep) | Power - TV Horizontal Output (sweep) |
| Construction | Pentode | Pentode |
| Base | 9AS | Noval |
| Socket | B9A | B9A |
| Base pins | 9 | 9 |
| Sections | 1 | 1 |
| Heater voltage | 21 V | 21.5 V |
| Heater current | 0.3 A | 0.3 A |
Power - TV Horizontal Output (sweep)
The database records 21B6 as a possible replacement for21A6.
No special restrictions are recorded for this substitution.
| Specification | Original tube | Replacement |
|---|---|---|
| Tube type | Power - TV Horizontal Output (sweep) | Power - TV Horizontal Output (sweep) |
| Construction | Pentode | Pentode |
| Base | 9AS | Not recorded |
| Socket | B9A | B9A |
| Base pins | 9 | 9 |
| Sections | 1 | 1 |
| Heater voltage | 21 V | 21.5 V |
| Heater current | 0.3 A | 0.3 A |
Where 21A6 can be used as the replacement
In these recorded relationships, 21A6 is the replacement tube. The listed original tubes are not automatically suitable as replacements for 21A6.
Power - TV Horizontal Output (sweep)
The database records 21A6 as a possible replacement forPL81.
No special restrictions are recorded for this substitution.
| Specification | 21A6 replacement | Original tube |
|---|---|---|
| Tube type | Power - TV Horizontal Output (sweep) | Power - TV Horizontal Output (sweep) |
| Construction | Pentode | Pentode |
| Base | 9AS | Noval |
| Socket | B9A | B9A |
| Base pins | 9 | 9 |
| Sections | 1 | 1 |
| Heater voltage | 21 V | 21.5 V |
| Heater current | 0.3 A | 0.3 A |
Power - TV Horizontal Output (sweep)
The database records 21A6 as a possible replacement for21B6.
No special restrictions are recorded for this substitution.
| Specification | 21A6 replacement | Original tube |
|---|---|---|
| Tube type | Power - TV Horizontal Output (sweep) | Power - TV Horizontal Output (sweep) |
| Construction | Pentode | Pentode |
| Base | 9AS | Not recorded |
| Socket | B9A | B9A |
| Base pins | 9 | 9 |
| Sections | 1 | 1 |
| Heater voltage | 21 V | 21.5 V |
| Heater current | 0.3 A | 0.3 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 21A6 specifications →