I got parts connexions # NOS-75306 which is described as "Sylvania JAN CHS 12AU7 / ECC82, Gold Logo, Short Black Ladder Plate, Medium-Mu Dual Triode, 9 pin, Original Box, USA". Though they really have green logo and markings. It also says 12AU7A on them. The ribbed black plates do look nice, and match my enclosure well. =P
Today I randomly noticed that I can hear humming from my transformer. If I place my hear directly on it, I can hear the same type of humming I often hear from step-down transformers on power lines. Is this normal, or a sign that it's overloaded? There's also another noise close to the mounts of the transformer, which is not quite the same as the white noise at the output. Wondering now what could be the cause of that. It may be current leaking trough the chassis.