For sale: tested vintage 12 AU7 & 12AU7A preamp & rectifier tubes. MANY AVAILABLE! Match your own sets! Brands available are RCA, Sylvannia, & General Instruments. Many date from the 1950's & 1960's.
CONDITION:
The tubes are in very good physical condition. Tubes were tested on HICKOK 539C by an experienced technician & values are written on each tube.
Minimum new tube Gm on HICKOK 539C = ~12au7/ecc82 1950 Gm
12AU7 or 12AU7A tubes
RCA
Triode 1 mAmp Triode 2 mAmp gain stage Date of Manufacture
2000 6.2 2200 6.4 audio +
2600 8.0 2700 8.6 audio + 1959
2650 7.8 2800 9.1 audio + 1958
2700 8.5 2600 8.0 low gain stage
2700 8.2 2700 8.2 audio + 1958
2650 8.0 2700 8.3 audio + 1958
2650 8.6 2400 7.6 audio + 1959
2200 6.7 2500 7.7 audio +
2100 7.1 2700 9.1 low gain stage
2300 6.9 2350 6.9 audio + 1958
2900 11.1 3100 10.2 audio +
SYLVANNIA
3000 9.9 2800 8.9 audio +
2200 7.0 2400 7.8 audio +
2200 6.7 2600 8.2 audio +
2050 6.5 2300 7.0 audio +
2200 6.9 2500 8.1 audio +
2550 7.7 2650 8.4 audio +
2400 7.1 2400 7.1 audio +
2800 8.9 2600 8.2 audio +
GENERAL INSTRUMENTS
2300 7.4 2400 7.7 audio + 1959
2550 8.8 2800 9.6 audio + 1959
MYSTERY BRAND/WORN OFF
2400 7.4 2500 7.6 audio +sss
PHILCO
2100 7.9 2050 6.9 low gain
12AT7 and 12AT7A TUBES
RCA
3700 4.0 3600 3.7 low gain
4250 4.7 3700 4.7 low gain 1957
3000 3.4 2900 4.2 low gain 1954
2800 2.9 2800 3.4 low gain
2900 3.1 3000 4.1 low gain 1958
4800 5.9 5000 6.7 low gain 1957
4200 4.7 4900 6.3 low gain 1960
5300 7.5 5100 6.0 low gain 1959
SYLVANIA
2900 3.1 4800 6.7 low gain
GENERAL INSTRUMENT
4400 5.4 4400 5.3 low gain 1959
4100 5.0 4600 6.3 low gain 1959
INTERNATIONAL
8500 11.1 9500 13 low gain
MYSTERY BRAND/NO LABEL
3000 3.3 3200 3.4 low gain
3900 4.0 4000 4.3 low gain
Preamp tube labels show both Plate Readings, and mA draw. Tubes have also been AUDIO TESTED in an actual audio circuit. Most tubes are tested suitable for audio gain stage. A few are suitable for low gain driver stage. Please specify which one wanted.
Tube testing was done by Nick at Wood Brothers in Pittsfield, MA. Testing documentation & paperwork from Nick/ModdJobs will be supplied if you buy 1 or 20.
Price $3.99