10 x 12ax7 Sylvania Tubes

Made in USA for Baldwin

Long Ribbed Grey plates

The lettering is smudged/missing


Tested on Hickok 6000A

1320/1300
1400/1320
1350/1340
1460/1330
1320/1500

1390/1320
1770/1740
1520/1580
1290/1500
1520/1490

Mutual conductance(100%) = 1250/1250


I do combine S&H when possible