[Winky Dink]

I didn't think this was hum. My impression was that 60-cycle hum would sound like it was imposed on top of the audio, but this sounds like the audio is rapidly cutting on-off. The prominence also seems to be frequency-dependent. At one end of the band it's barely noticeable. This sounds like someone talking through the turning blades of a fan.

Filter caps were replaced with new electrolytics very close to original values, but I'll re-check my connections.

Thanks.