RCA Radiotron UX-226 Type 26 Globe NOS c1929 Original Box Insert Triplett Tested

Listing details

A beautiful piece of early RCA history that also happens to test exceptionally well.

This is a genuine RCA Radiotron UX-226 / Type 26 globe vacuum tube, conservatively dated circa 1929, accompanied by its period RCA UX-226 box, original protective wrapping and surviving RCA factory insert.

The classic silvered globe, engraved RCA Radiotron base and early four-pin construction give this tube the unmistakable character of late-1920s RCA production. It is the kind of vintage component that is enjoyable simply to hold and look at—but this example also offers the reassurance of documented electrical performance.

Triplett 3444 Test Results

Transconductance: 930 µmhos

Plate current: 3.5 mA

Triplett 3444 Type 26 reference:

Average reference: 900 µmhos

Reject point: 580 µmhos

This tube therefore measured slightly above the Triplett average transconductance reference during testing.

Rather than simply describing an antique tube as “strong” or assigning an unsupported percentage, I prefer to provide the actual measured values so the buyer knows exactly what was observed.

Vintage New Old Stock

This tube has not been put into service. It was tested electrically before sale so its present performance could be documented. Testing does not change its NOS status; it remains vintage unused stock.

Period RCA presentation

Included with the tube:

Original period RCA Radiotron UX-226 box

Original protective paper wrapping

Surviving RCA factory insert

The cardboard box shows genuine age and storage wear, including edge wear, creasing, discoloration and wear around the upper portion. Nothing has been cosmetically restored. The box-bottom marking “G 3-29” is preserved and visible; because I have not found definitive RCA documentation decoding that marking, I am conservatively describing the tube as circa 1929 rather than assigning an exact production month.

Where the UX-226 / Type 26 belongs

The UX-226 was an important early AC-filament triode used in late-1920s radio and audio-frequency amplification. It is an excellent choice for restoration of compatible RCA Radiola and other period AC radio equipment designed for the UX-226 / Type 26.

The Type 26 also remains of interest to enthusiasts building or restoring directly heated triode line-stage, preamplifier and driver circuits.

Always confirm that UX-226 / Type 26 is the correct tube for the exact equipment before installation.

Why this example stands out

It combines the things collectors and restorers hope to find together:

Genuine RCA Radiotron UX-226 globe construction

Vintage New Old Stock condition

Period RCA box and factory literature

Attractive silvered globe

Original engraved RCA Radiotron base

Documented Triplett 3444 performance

930 µmhos versus a 900 µmhos Triplett average reference

The exact tube and packaging shown are what you will receive.

Carefully packed for secure shipment.

Supplied by VTubeAudio.

Results reflect measured performance at the time of testing.

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