4x RCA 6CG7 6FQ7 

Clear Top Side Getter 

NOS tested matched quad Industrial Brazil.

Bought from a radio station that was supplied direct from RCA.

Taken from a batch/box of 100.

Manufactured in Brazil in the late 80's using equipment and materials imported from the USA.

These are low in micromhos and might last 3/4 of a new avarage but still sound great. I have tried similar and no noticable difference. in audio quality (a new average is 100% @ 2600/2600 micromhos @ 9.0/9.0 mA +/- 10%).

Tube 1 - 2200/2200

Tube 2 - 2200/2200

Tube 3 - 2200/2200

Tube 4 - 2200/2200