Mechanic's Stethoscope & Hearing Aids

Trust me, I am well aware of how you can fool yourself with these.  I once diagnosed a bad tensioning pulley on a Subaru (it was actually bad) only to replace it and find that the idler pulley was much in much worse shape and exploded out through the timing belt cover milliseconds after starting the engine.  Bent valves and bad language followed...

Anyway, I sometimes find a cheap stethoscope is very helpful.  But I am 68 and started wearing hearing aids last year.  Now I have to remove the h/a to use a cheap stethoscope.  That's ok for a rumble but hopeless for any higher frequency sounds.  Has anyone figured out a cheap way to get around this?  

The only thing I can think of is an electronic stethoscope that I can use with over the ear headphones.  They do make such a device but I'm not bringing home doctor money these days.  (Improvements in the h/a technology mean that I can use over the ear headphones without feedback.)  

When I was in auto shop in high school I used to hold an old vacuum cleaner hose to my ear and poke around the engine compartment with the other end, to the great amusement of everyone around me.  Sometimes I miss those days.

This belt install tool is my favorite listening stick.
 

The T handle is plastic and nestles in my ear perfectly.

I have been experimenting with a knock sensor bolted onto a length of tube as well to make a kind of "visual stethoscope" for the lab scope with mixed results

I think I found what I need while watching a South Main Auto video. It looks like the Steelman Chassis Ear comes with over the ear headphones. I should be able to leave the hearing aids in and use this to find noises.

And someday when I have a noise that can't be duplicated in a repair stall I'll have this available.

Thank your lucky stars if you have no idea what I'm talking about here. Old age comes quickly!