"Mike Rivers" wrote in message
news:znr1057625329k@trad...

In article writes:

One thing I've discovered that's kind of interesting is that I can tell
when a device has a bad transformer just by putting a finger on the
chassis. It feels to me as though it's vibrating or trembling.

Just about anything with a power transformer is going to be pumping
measurable and perhaps audible vibration into the chassis. The major
operative phenomina are both normal magnetic attraction and repulsion, as
well as magnetostriction.

Mechanical vibration of transformer windings can indeed be a source of
acoustic noise. I suppose that it's possible to feel the vibration
before you can hear it. But usually it's the power transformer that's
got the loose windings or core laminations. Have you been able to
isolate the "feel" of a signal transformer and feel it vibrate along
with the audio?

Given that Boyk is into tubes, there's a likely explanation...