Product Description

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

Product Specs

Condition:Very Good Make:RCA Model:12AU7 Categories:Tubes