MESA Engineering 12AX7 ECC83 Preamp Vacuum Tube - Strong B&K 747 Tested
$24.95
Genuine MESA Engineering branded 12AX7/ECC83 high-gain dual-triode preamplifier vacuum tube. The original MESA Engineering branding remains visible, with normal cosmetic wear to portions of the printed markings.
This individual tube was bench tested on a B&K Model 747 Dynamic Mutual Conductance Tube Tester. Both triode sections tested strongly within the GOOD range. Triode Section 1 measured approximately 98, while Triode Section 2 measured approximately 108. Both sections show strong output, although this tube is not represented as precision balanced.
The 12AX7 is a nine-pin high-mu dual triode commonly used in guitar amplifiers, bass amplifiers, hi-fi equipment, stereo systems, microphone preamplifiers, voltage-amplifier stages, driver stages, and phase-inverter circuits. The tube shown in the photographs is the actual tube being sold.
Historical Note: MESA Engineering, widely known through the MESA/Boogie amplifier brand, has supplied selected and branded vacuum tubes for professional guitar and bass amplification equipment. MESA-branded 12AX7 tubes have been widely used as original equipment and replacement tubes in classic, modern, and high-gain amplifier circuits.
Compatible Radios / Boards
Compatible with equipment designed for 12AX7, 12AX7A, ECC83, 7025, and equivalent nine-pin high-gain dual-triode vacuum tubes where circuit requirements permit. Suitable for many MESA/Boogie and other compatible guitar amplifiers, bass amplifiers, hi-fi amplifiers, stereo equipment, tube preamplifiers, microphone preamps, voltage-amplifier stages, 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 98 within the GOOD range. Triode Section 2 tested at approximately 108 within the GOOD range. Both triode sections tested strong, with approximately a 10 percent difference between readings. Heater operation confirmed and no shorts indication was observed during testing. Noise and microphonics were not evaluated. Actual tube and test photographs are included.
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