It's time to restore the 11/45.

[tony duell]

> 
> That amounts to a differential (rather than single-ended) input, and I
> would consider that the _right_ way to do it.  But, of course, that
> costs, and single-ended is plenty good enough for most purposes, so
> that's what most scopes do. :-(

Even when a 'scope has true differential inputs the common-mode range
may not be large enough to include mains. 

-tony