ARS-Branded JJ/Tesla 6BQ5 / EL84 Closely Matched Quad Tested Power Output Vacuum Tubes
$89.95
Closely matched quad of four ARS-branded 6BQ5 / EL84 power-output vacuum tubes carrying “JJ/Tesla” production markings. Each tube is marked “ARS Since 1947 Van Nuys, Calif.” and was individually tested under the same settings and warm-up procedure on a B&K Model 747 Dynamic Mutual Conductance tube tester. The four relative quality readings measured approximately 69, 69, 68, and 69, producing an exceptionally close one-point spread across the complete set. Suitable for guitar amplifiers, tube audio amplifiers, receivers, radios, and other equipment designed for a quartet of EL84 / 6BQ5 output tubes. Historical Note: ARS was a long-established California tube supplier and private-label brand based in Van Nuys. The ARS marking identifies the distributor and brand, while the visible JJ/Tesla marking indicates the tube-production source. The EL84, also known by its American designation 6BQ5, became one of the most widely used compact audio-output pentodes in guitar amplifiers, radios, and hi-fi equipment.
Compatible Radios / Boards
Suitable for equipment designed for EL84, 6BQ5, and compatible nine-pin power-output pentodes when approved by the equipment manufacturer. Common applications include guitar amplifiers, tube hi-fi amplifiers, receivers, radios, and push-pull audio-output stages. Suitable for many amplifiers using four EL84 tubes, including numerous 30-watt-class guitar amplifiers. Buyer must verify tube type, socket wiring, plate voltage, heater supply, bias requirements, amplifier specifications, and equipment compatibility before installation.
RF Boneyard Bench Notes
All four tubes were tested individually on a B&K Model 747 Dynamic Mutual Conductance tube tester using the same 6BQ5 chart settings and warm-up procedure. Tube 1 measured approximately 69, Tube 2 measured approximately 69, Tube 3 measured approximately 68, and Tube 4 measured approximately 69 on the tester’s relative quality scale. All four tubes tested within the GOOD range. Total spread across the quad is approximately one scale point, or about 1.5%, supporting description as a closely matched quad based on B&K 747 relative quality readings. Heaters operated normally and no shorts indication was observed during testing. This set is not represented as laboratory plate-current matched, direct-micromho matched, or amplifier burn-in matched.
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