I have 3 old 6Y6 power tubes...an RCA, a Raytheon, and a Ward's Airline. The Raytheon is definitely a blackplate, and I'm pretty sure that the RCA is a blackplate, from what I can see through the smoked glass. Not sure about the Airline. Anyway, I've heard that these can be substituted for 6V6s in low wattage amps, such as Champs. I put one of them in my s/f Champ and it sounded good. Anybody else here have any experience with 6Y6s?