Great sounding hard to find tube, n.i.b. and fresh from the shelf. If you don't buy them they won't make them!

I work on a lot of vintage Gibson, and National amps. The 6EU7 was a hi fi tube well on par with a real 7025 low noise high performance 12AX7A, only with a different pin out, and the lack of a 12 volt heater option. The heater and pin out in the older 6EU7s made them easier to match sections, and the gain was almost always higher than a 12AX7 too. If you look in the manuals, the 12AX7, and the 6EU7 share the same exact transfer curve plots, but the 6EU7 was usually a better tube as far as American brands went. The 6EU7 also has lower internal capacitances too. This looks like a rebranded Sovtek, and they test about as well too. Mediocre at best! One section is usually way above the other with a plate current mismatch of up to 50%. The transconductance is also usually badly mismatched too. Since no one else makes a 6EU7, Mike Mathews has taken the typical New Sensor unique product stance. "It is terrible, but who else you gonna buy one from, so we don't care how bad they are". If you have an amp that uses 6EU7s rewire the sockets for 12AX7s, or Soviet military 6N2P. Maybe someday I will actually get a good batch of these, but the only reason I am not giving them one star, is no one else makes one, and they have improved, but not very much. The Sovtek 6Eu7s were absolutely horrific. No one would even attempt to match sections for a phase inverted, they were that bad, and they have the gall to charge over $20 for these.