common as grass.
http://p.globalsources.com/IMAGES/PDT/BIG/980/B1051156980.jpg
tv-5 will work fine as well. Just about any old amp that has a push button power switch is of the same design and mount. ie, a 50 wpc integrated/receiver from 1975 to 1999 will generally have a tv-5 for a push button power switch. old push button powered cd players/changers will have the tv-3. Any yamaha/kenwood/denon/etc will do!
Find the local scrap pile or repair shop,and you’ll get one in minutes. That is, if time is an issue.