Art Audio only sells Grade A Tubes from Sophia Electric in matched pairs or quads.
This new blue glass 6SN7 has rich tonality and big sound stage. Designed to compliment to Aqua 274B and Classic 300B tubes, the new 6SN7 is a great choice to replace vintage 6SN7 tubes in all tube pre-amplifiers and tube amplifiers.
6SN7, like all dual triode tube, has two sections. To match the two sections closely enough is hard enough; matching two tubes--four sections--would be much harder if high standard of matching method is applied.
Note: Some internet vendors would only test one section of the tube due to the limitation of their vintage tube tester (like popular TV-7). So those claimed to be matched may be matched by one section only, with assumption that the two sections would be identical. However, that assumption is false one.
This tube usually ships within 2-4 business days.