Soviet NOS Substitute for 6SN7GT

[Chris K]

The 6SN7 tubes are skyrocketing in price and being sold on eBay in groups of "matched pairs or quads" for the exploding vintage audio craze. I've been getting some tubes from vivatubes.com and bought 4 Soviet era NOS 6N8S substitutes for the 6SN7GT for $40...$10 each. So far, they seem to work well. I don't know if they are built to the standards of other Soviet era vacuum tubes, but these have a reputation for being overbuilt. We'll see. Anyone tried these tubes or other substitute swaps using tubes from the nation formally known as "The Evil Empire"?