understanding this schematic

[mike_odonovan]

hey this is my first post on here so be kind.
have been learning schematics and doin a couple of mods on amps but i was looking at building one of these -
http://i330.photobucket.com/albums/l...chematic-3.jpg
i understand everthing in the schem except the triangle symbols, what are they?
also anyone ever put one in an amp yet?

[hasserl]

Op-amps Operational amplifier - Wikipedia, the free encyclopedia

[mike_odonovan]

thanks hasserl - i learn somthing every day