Tube cross-reference
1A4 alternatives, equivalents, and replacements
Review exact electrical variations and directional substitutions recorded for the 1A4 voltage pentode. Compare core specifications and verify every restriction before using a replacement.
Replacement tubes for 1A4
The following tubes are recorded as possible replacements for 1A4. This direction does not establish that 1A4 can replace them.
Voltage Pentode - Remote Cutoff (single)
The database records 1A4P as a possible replacement for1A4.
No special restrictions are recorded for this substitution.
| Specification | Original tube | Replacement |
|---|---|---|
| Tube type | Voltage Pentode | Voltage Pentode - Remote Cutoff (single) |
| Construction | Pentode | Pentode |
| Base | Not recorded | 4M |
| Socket | Not recorded | UX4 |
| Base pins | Not recorded | 4 |
| Sections | 1 | 1 |
| Heater voltage | 2 V | 2 V |
| Heater current | 0.06 A | 0.06 A |
Voltage Pentode - Remote Cutoff (single)
The database records 1A4T as a possible replacement for1A4.
No special restrictions are recorded for this substitution.
| Specification | Original tube | Replacement |
|---|---|---|
| Tube type | Voltage Pentode | Voltage Pentode - Remote Cutoff (single) |
| Construction | Pentode | Pentode |
| Base | Not recorded | 4K |
| Socket | Not recorded | UX4 |
| Base pins | Not recorded | 4 |
| Sections | 1 | 1 |
| Heater voltage | 2 V | 2 V |
| Heater current | 0.06 A | 0.06 A |
Voltage Pentode - High Frequency (single)
The database records 1B4 as a possible replacement for1A4.
No special restrictions are recorded for this substitution.
| Specification | Original tube | Replacement |
|---|---|---|
| Tube type | Voltage Pentode | Voltage Pentode - High Frequency (single) |
| Construction | Pentode | Pentode |
| Base | Not recorded | Not recorded |
| Socket | Not recorded | Not recorded |
| Base pins | Not recorded | 5 |
| Sections | 1 | 1 |
| Heater voltage | 2 V | 2 V |
| Heater current | 0.06 A | 0.06 A |
Voltage Pentode - Sharp Cutoff (single)
The database records 1B4P as a possible replacement for1A4.
No special restrictions are recorded for this substitution.
| Specification | Original tube | Replacement |
|---|---|---|
| Tube type | Voltage Pentode | Voltage Pentode - Sharp Cutoff (single) |
| Construction | Pentode | Pentode |
| Base | Not recorded | 4M |
| Socket | Not recorded | UX4 |
| Base pins | Not recorded | 4 |
| Sections | 1 | 1 |
| Heater voltage | 2 V | 2 V |
| Heater current | 0.06 A | 0.06 A |
Voltage Pentode
The database records 1K4 as a possible replacement for1A4.
- Parallel heater circuits only
| Specification | Original tube | Replacement |
|---|---|---|
| Tube type | Voltage Pentode | Voltage Pentode |
| Construction | Pentode | Pentode |
| Base | Not recorded | Not recorded |
| Socket | Not recorded | UX4 |
| Base pins | Not recorded | 4 |
| Sections | 1 | 1 |
| Heater voltage | 2 V | 2 V |
| Heater current | 0.06 A | 0.12 A |
Voltage Tetrode
The database records 32 as a possible replacement for1A4.
No special restrictions are recorded for this substitution.
| Specification | Original tube | Replacement |
|---|---|---|
| Tube type | Voltage Pentode | Voltage Tetrode |
| Construction | Pentode | Tetrode |
| Base | Not recorded | 4K |
| Socket | Not recorded | UX4 |
| Base pins | Not recorded | 4 |
| Sections | 1 | 1 |
| Heater voltage | 2 V | 2 V |
| Heater current | 0.06 A | 0.06 A |
Voltage Pentode - Remote Cutoff (single)
The database records 34 as a possible replacement for1A4.
No special restrictions are recorded for this substitution.
| Specification | Original tube | Replacement |
|---|---|---|
| Tube type | Voltage Pentode | Voltage Pentode - Remote Cutoff (single) |
| Construction | Pentode | Pentode |
| Base | Not recorded | 4M |
| Socket | Not recorded | IO |
| Base pins | Not recorded | 7 |
| Sections | 1 | 1 |
| Heater voltage | 2 V | 2 V |
| Heater current | 0.06 A | 0.06 A |
Voltage Pentode - High Frequency (single)
The database records 951 as a possible replacement for1A4.
No special restrictions are recorded for this substitution.
| Specification | Original tube | Replacement |
|---|---|---|
| Tube type | Voltage Pentode | Voltage Pentode - High Frequency (single) |
| Construction | Pentode | Pentode |
| Base | Not recorded | Not recorded |
| Socket | Not recorded | UX4 |
| Base pins | Not recorded | 4 |
| Sections | 1 | 1 |
| Heater voltage | 2 V | 2 V |
| Heater current | 0.06 A | 0.06 A |
Where 1A4 can be used as the replacement
In these recorded relationships, 1A4 is the replacement tube. The listed original tubes are not automatically suitable as replacements for 1A4.
Voltage Pentode - Remote Cutoff (single)
The database records 1A4 as a possible replacement for1A4P.
No special restrictions are recorded for this substitution.
| Specification | 1A4 replacement | Original tube |
|---|---|---|
| Tube type | Voltage Pentode | Voltage Pentode - Remote Cutoff (single) |
| Construction | Pentode | Pentode |
| Base | Not recorded | 4M |
| Socket | Not recorded | UX4 |
| Base pins | Not recorded | 4 |
| Sections | 1 | 1 |
| Heater voltage | 2 V | 2 V |
| Heater current | 0.06 A | 0.06 A |
Voltage Pentode - Remote Cutoff (single)
The database records 1A4 as a possible replacement for1A4T.
No special restrictions are recorded for this substitution.
| Specification | 1A4 replacement | Original tube |
|---|---|---|
| Tube type | Voltage Pentode | Voltage Pentode - Remote Cutoff (single) |
| Construction | Pentode | Pentode |
| Base | Not recorded | 4K |
| Socket | Not recorded | UX4 |
| Base pins | Not recorded | 4 |
| Sections | 1 | 1 |
| Heater voltage | 2 V | 2 V |
| Heater current | 0.06 A | 0.06 A |
Voltage Pentode - High Frequency (single)
The database records 1A4 as a possible replacement for1B4.
No special restrictions are recorded for this substitution.
| Specification | 1A4 replacement | Original tube |
|---|---|---|
| Tube type | Voltage Pentode | Voltage Pentode - High Frequency (single) |
| Construction | Pentode | Pentode |
| Base | Not recorded | Not recorded |
| Socket | Not recorded | Not recorded |
| Base pins | Not recorded | 5 |
| Sections | 1 | 1 |
| Heater voltage | 2 V | 2 V |
| Heater current | 0.06 A | 0.06 A |
Voltage Pentode - Sharp Cutoff (single)
The database records 1A4 as a possible replacement for1B4P.
No special restrictions are recorded for this substitution.
| Specification | 1A4 replacement | Original tube |
|---|---|---|
| Tube type | Voltage Pentode | Voltage Pentode - Sharp Cutoff (single) |
| Construction | Pentode | Pentode |
| Base | Not recorded | 4M |
| Socket | Not recorded | UX4 |
| Base pins | Not recorded | 4 |
| Sections | 1 | 1 |
| Heater voltage | 2 V | 2 V |
| Heater current | 0.06 A | 0.06 A |
Voltage Pentode
The database records 1A4 as a possible replacement for1K4.
- Parallel heater circuits only
| Specification | 1A4 replacement | Original tube |
|---|---|---|
| Tube type | Voltage Pentode | Voltage Pentode |
| Construction | Pentode | Pentode |
| Base | Not recorded | Not recorded |
| Socket | Not recorded | UX4 |
| Base pins | Not recorded | 4 |
| Sections | 1 | 1 |
| Heater voltage | 2 V | 2 V |
| Heater current | 0.06 A | 0.12 A |
Voltage Tetrode
The database records 1A4 as a possible replacement for32.
No special restrictions are recorded for this substitution.
| Specification | 1A4 replacement | Original tube |
|---|---|---|
| Tube type | Voltage Pentode | Voltage Tetrode |
| Construction | Pentode | Tetrode |
| Base | Not recorded | 4K |
| Socket | Not recorded | UX4 |
| Base pins | Not recorded | 4 |
| Sections | 1 | 1 |
| Heater voltage | 2 V | 2 V |
| Heater current | 0.06 A | 0.06 A |
Voltage Pentode - Remote Cutoff (single)
The database records 1A4 as a possible replacement for34.
No special restrictions are recorded for this substitution.
| Specification | 1A4 replacement | Original tube |
|---|---|---|
| Tube type | Voltage Pentode | Voltage Pentode - Remote Cutoff (single) |
| Construction | Pentode | Pentode |
| Base | Not recorded | 4M |
| Socket | Not recorded | IO |
| Base pins | Not recorded | 7 |
| Sections | 1 | 1 |
| Heater voltage | 2 V | 2 V |
| Heater current | 0.06 A | 0.06 A |
Voltage Pentode - High Frequency (single)
The database records 1A4 as a possible replacement for951.
No special restrictions are recorded for this substitution.
| Specification | 1A4 replacement | Original tube |
|---|---|---|
| Tube type | Voltage Pentode | Voltage Pentode - High Frequency (single) |
| Construction | Pentode | Pentode |
| Base | Not recorded | Not recorded |
| Socket | Not recorded | UX4 |
| Base pins | Not recorded | 4 |
| Sections | 1 | 1 |
| Heater voltage | 2 V | 2 V |
| Heater current | 0.06 A | 0.06 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 1A4 specifications →