Sound great, don't last very long
I usually use these in V1 of my 90's era Peavey Classic 30. Great gain, vintage sound, good grind and tone with no fizziness. On the downside, the newer ones don't last as long as the old ones used to. They go microphonic pretty quickly inside this amp, and I keep the amp well maintained and biased by a local tech. If the sound quality of this tube could be duplicated in one that is much more durable I'd be very happy. But my feeling is that at 18 USD it might not be worth it anymore. I'm gonna try an Electro Harmonix 12AX7 next.