How can I limit the volume on integrated amp

I would just get a network stereo receiver and some cheap but decent small used bookshelf speakers and encourage low level listing.  Just my guess but most renters probably would not care too much about sound quality just as long as they have music.  Or just get an AVR that has max turn on volume as well as max volume settings.

Bill

Your "guests" can listen through their  Iphone. They're just there to sleep anyhow.We have Air BnB's in the neighborhood. People in and out, on a daily basis. Inconsiderate,entitled and unwanted.

Absolutely the worst idea for a business, save for the property owner and user. Ruins the fabric of the neighborhood.
Don't give them an opportunity to annoy the neighbors.

Disregard if you're not operating one of these operations, though I'm guessing you may.

It's a beach condo. It's made for weekly rentals. I plan to spend a few weeks a year there and it'd be nice to have a decent system to use while I'm there.

After reading the responses I'm thinking a cheap bluetooth sound bar is the way to go.

A resistor in line with the inputs will drop the input voltage as much as you want. The volume can then be turned up all the way and not be very loud. It won't hurt anything and if switched would enable you to turn it off and back to normal when you are there. Anyone using it will simply think its not a very good (loud) stereo. Total cost, a couple resistors, next to nothing.

There are a couple ways of doing this. Least invasive but also least effective is to put the resistor in line with the RCA connectors of whatever is plugged in. Problems with this are you have to do it for each connection, and it doesn't protect in case they plug their iPod into a jack. The better but more involved solution is to open it up and follow the inputs to the selector switch and install the resistor at that point. This way no matter what input is selected they all get trimmed. That is all you're doing by the way, trimming the input, same as the volume control does. You are basically just adding another (fixed) volume control.

This is the more elegant solution but it does require a bit more study and being able to follow the wires inside, and then you would have to figure out how to switch it. Anyway, there's your options.

Set up a small system for your use only.  Spell it out in you listing agreement and remove the detachable power cable.  For your guest a bluetooth loudspeaker is more than sufficient.