H, I've a pair of jj el84s in my dt25 amp, but they are not matched (by about 10mv). I can't hear hny difference, besides a deep hum noise, but I read somewhere that unmatched tubes cao magnetize the output transformer in some way. That doesn't sound nice. Can I swop the tube positions to undo any magnetization? Is it aload of bs? Thoughts?
Magnetizing the OT is definitely a real thing, but it's not nearly as bad as it sounds. It's not permanent and it typically only happens when the tubes are so mismatched that they sound bad anyway. I wouldn't worry about it.