Got my final invoice today and they took another 15% off...bonus.
There are two types, one with a plastic base (not so hot) and one with the metal base (what this offer is/was and apparently desirable.)
From Brent Jesse's website:
6H8C:
This is a rather difficult to find Russian made tube that is a direct replacement for the 6SN7. This tube can be confusing to buy for the novice, as there are several versions available. The common version has a medium glass envelope and a black plastic base, and are still in production in Russia. They are of fair to medium quality, but certainly are not worth much more than $20.00 each. I have seen these tubes sold for export to the West, labelled as 6SN7GT. THE RARE VERSION, and the one to look for is the Russian military version. This tube has a medium glass envelope, with a nickel collar around the base. It has black T-shaped plates facing each other, with small holes in the sides of the plates. There may be an "OTH" production number inked on the base, and the tube type is etched within a circle on the glass. These military tubes are rare, and are built like the Tung Sol oval plates, with spring mounted spacers at the top touching the inside glass, and heavy support rods for each plate element. These tubes have incredible air and accurate bass, kind of like what a Telefunken sounds like! They are amazingly dynamic, and at the same time delicate, and very quiet. These tubes are actually rarer than the fabeled Tung Sol oval plates, and clients have told me these sound better!
