Vintage Motorola 12AX7A ECC83 Dual Triode Vacuum Tube - Balanced B&K 747 Tested
$34.95
Vintage Motorola-branded 12AX7A/ECC83 high-gain dual-triode vacuum tube with gray-plate construction. The original red Motorola branding remains visible, although portions of the printed markings show age-related wear.
This individual tube was bench tested on a B&K Model 747 Dynamic Mutual Conductance Tube Tester. Both triode sections tested within the GOOD range at approximately 80 on the tester scale. The two sections produced nearly identical readings and are closely balanced.
The 12AX7A is a nine-pin high-mu dual triode commonly used in guitar amplifiers, bass amplifiers, hi-fi equipment, stereo systems, microphone preamplifiers, driver stages, and phase-inverter circuits. The tube shown in the photographs is the actual tube being sold.
Historical Note: Motorola marketed branded receiving tubes for radio, television, communications, and electronic-service applications during the vacuum-tube era. Like many equipment manufacturers, Motorola sourced some branded tubes from established tube factories. No specific original factory is claimed for this tube because a readable manufacturer code has not been documented.
Origin Tracker
Bench Stock
Pulled from RF Boneyard bench/service stock for practical repair and restoration use.
Pipeline quantities are informational and may change after arrival, inspection, sorting, testing, or donor teardown.
Compatible Radios / Boards
Compatible with equipment designed for 12AX7A, 12AX7, ECC83, 7025, and equivalent nine-pin high-gain dual-triode vacuum tubes where circuit requirements permit. Common applications include guitar amplifiers, bass amplifiers, hi-fi amplifiers, stereo equipment, tube preamplifiers, microphone preamps, driver stages, and phase-inverter circuits. Buyer should verify the required tube type before installation.
RF Boneyard Bench Notes
Tested on a B&K Model 747 Dynamic Mutual Conductance Tube Tester. Triode Section 1 tested at approximately 80 within the GOOD range. Triode Section 2 tested at approximately 80 within the GOOD range. Both triode sections produced nearly identical readings and are closely balanced. Heater operation confirmed. Actual tube and test photographs are included.
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