Cunningham CX-326 Type 26 Globe Tube - Amplitrex Tested Strong Engraved Base

Listing details

Cunningham CX-326 Type 26 Globe Triode — Amplitrex AT1000 Tested

Offered here is one well-preserved Cunningham CX-326 globe tube with its engraved black base and period Straus-Frank Co. dealer or service label.

This is the exact tube shown throughout the photographs. It has been individually tested, carefully documented, and supplied in a new white replacement box with a printed test record.

Amplitrex AT1000 test results

Plate current: 6.6 mA

Transconductance: 1.00 mA/V / 1,000 µmhos

AT1000 reference values:

Plate current: 6.2 mA

Transconductance: 1.10 mA/V / 1,100 µmhos

The measured plate current was slightly above the AT1000 reference value, with transconductance measuring approximately 91% of reference.

No shorts or abnormal leakage were detected during testing.

No audible internal rattle was heard when the tube was gently handled.

Physical condition

The glass envelope is intact, the internal structure appears complete and stable, and the getter flashing remains substantial. The engraved Cunningham and CX-326 base markings remain readable.

The four pins show normal age-related surface wear and discoloration, all documented in the close photographs.

A period paper label from Straus-Frank Co., San Antonio and Houston, Texas, remains attached to the glass. The label is aged, discolored, torn, and incomplete. It has intentionally been left in place as part of the tube’s history and appearance.

Please examine all photographs carefully. They document the actual glass, getter, internal structure, engraved base, period label, and pin condition.

Included

One Cunningham CX-326 Type 26 globe tube

One new white replacement tube box

One printed Amplitrex AT1000 test card

The box is a new protective replacement and is not original Cunningham packaging.

No stock photographs or substitute tubes are being used. The exact tube pictured is the tube the buyer will receive.

The tube will be securely packed to protect the globe envelope, glass-to-base junction, engraved base, pins, and period paper label during shipment.

A strong, carefully tested and clearly documented Cunningham CX-326 for an antique-radio restoration, Type 26 audio project, or early vacuum-tube collection.

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