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For the full breakdown, see our best 5AR4 Tube guide.
One wrong tube swap can take out an output transformer, and the limits inside a 5AR4 rectifier tube datasheet are what prevent it.
The table below pulls the ratings into one place, and the notes after cover replacements and safety.
5AR4 Datasheet: Core Electrical Ratings
These ratings decide whether the tube survives a new build or a replacement.
| Specification | Published Value | What To Check |
|---|---|---|
| Type | Full-wave, indirectly heated, octal base | Matches the socket wiring in the amp |
| Heater voltage | 5.0 V AC | Transformer’s 5 V rectifier winding |
| Heater current | 1.9 A on Mullard/Philips data; 1.7–2.1 A on modern sheets | Confirm against the exact brand’s datasheet |
| Max DC output current | 250 mA | Sustained loads above this stress the plates |
| Max RMS plate voltage | 550 V | Some sheets differ; check application data |
| Max peak inverse voltage | 1500 V (one CV1377 sheet lists 2800 V) | Verify before high-voltage designs |
| Max first filter capacitor | 60 µF | Exceeding this shortens tube life |
| Typical application | 550-0-550 V RMS, 160 mA, 60 µF, 175 Ω series resistance | Useful starting point for new designs |
Dimensional differences between brands are small but real, so check socket clearance before ordering.
Can A 5AR4 Replace A 5Y3 Or GZ34?
The 5AR4 is the American RETMA designation for the European GZ34,