Hello...a quick question looking for a good suggestion/solution/answer,

1) I have a small rural nursing school;
2) I have a $500 electronic stethoscope (micro-battery powered) that can
hear/play/record sounds using an I-Pod by using a direct wire/plug into the
I-Pod external microphone jack;
3) I-Pod sounds are very weak and you have to be within inches to hear the sound
during playback;
4) I need a room full of 10 students to hear the sounds from the stethoscope;
5) I connected it to a wall-plug store-bought powered I-Pod speaker sound system
and it worked great...everybody in room could hear the sounds fine!;
6) Was then informed it could possibly be a major shock hazard (110 power from
wall through speakers to stethoscope to person wearing (ear pieces) and to
patient's chest (diaphragm);
7) So...now I'm back to Step 1 & 2...

Any suggestions on how I could truly prevent a surge danger for under $100 bucks
so that I can safely use the stethoscope and the powered speaker system?
Would an automotive quick-jump power pack with 110 inverter work or would the
danger still be present? Is there really even a danger in the first place?

Thank you very much for your wisdom, advice and expertise!

William in Colorado