NEW OLD STOCK PLATINUM MATCHED PAIR MULLARD BLACKBURN 12AU7 ECC82 CODE MATCHED TESTED

Up for sale is a premium matched pair of Amperex-labeled Mullard Blackburn 12AU7A / ECC82 vacuum tubes, both carrying matching B3H4 etched Blackburn factory/date codes. These were manufactured by Mullard Blackburn, England, and labeled for Amperex. The B3H4 code dates them to 1963, August, 4th week.

This is a beautiful same-code pair with near-perfect labels and crisp original boxes. Both tubes test extremely strong and closely matched on my MaxiMatcher preamp tube tester. They were also tested for noise and microphonics with excellent results.

Test Results:

Tube 1:Gain: 16.4 / 16.4Transconductance: 1.47 / 1.43 mA/VNoise: -85.1 / -85.3 dBMicrophonics: Very low, barely audible tap

Tube 2:Gain: 16.1 / 16.4Transconductance: 1.46 / 1.46 mA/VNoise: -85.8 / -85.8 dBMicrophonics: Very low, barely audible tap

This is what I would consider a platinum-matched, low-noise, low-microphonic pair. Gain is matched extremely closely across all four triode sections, and transconductance is also very tightly matched. These are strong NOS-level testing tubes and should be excellent for high-quality audio use, including preamp stages, driver stages, phase inverter positions, headphone amplifiers, hi-fi equipment, and other circuits using 12AU7 / ECC82 types.