Matched Pair Cunningham CX-326 Type 26 Globe Tubes - Amplitrex AT1000 Tested

Listing details

Matched Pair of Cunningham CX-326 Type 26 Globe Triodes

Offered here is a carefully selected and closely matched pair of early Cunningham CX-326 globe tubes with engraved black bases and attractive original getter flashing.

These are the exact two tubes shown throughout the photographs. Both are clearly marked Cunningham CX-326 and share the same general envelope, plate, base, and internal construction.

Amplitrex AT1000 test results

Each tube was individually evaluated on an Amplitrex AT1000.

Tube A

Plate current: 4.5 mA

Transconductance: 1,000 µmhos

Tube B

Plate current: 4.7 mA

Transconductance: 1,000 µmhos

AT1000 reference values

Plate current: 6.2 mA

Transconductance: 1,100 µmhos

The pair measured identically for transconductance, with only a 0.2 mA difference in plate current. No shorts or leakage were detected during testing.

Neither tube has an audible internal rattle when gently handled.

Physical condition

Both tubes retain clear Cunningham CX-326 engraved-base markings, intact glass envelopes, complete internal structures, and substantial getter flashing.

The bases and pins show normal age-related cosmetic wear consistent with tubes of this period. Please examine the detailed photographs of the glass, plates, getters, bases, and pins.

No original factory boxes are included. Each tube will be supplied in a new white replacement box with its individual Amplitrex test card.

Included

Two Cunningham CX-326 Type 26 globe tubes

Two new white replacement tube boxes

Two individual Amplitrex AT1000 test cards

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

These tubes will be individually protected and securely packed to safeguard the globe envelopes, engraved bases, glass-to-base junctions, and four-pin connections during shipment.

A well-presented, accurately documented pair for an antique-radio restoration, Type 26 directly heated triode project, or Cunningham tube collection.

Please review all photographs carefully.

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