ok lang naman ang 2nd hand stuffs eh...but you really have to check it...kasi electronics yan...mahirap mag gamble...ako both of my amps are 2nd hand stuffs...but i biought them sa mga friends ko na kilala ko talaga and i know the history of the amp...kung saan ginamit...pano gamitin....

ask the seller kung ilang taon/months na ginagamit....
what is the amp powering....(seps?subz?)
pano niya gamitin (sq or spl?)

you can get 2nd hand stuffs sa mga boards here like kotse...ai...etc....

but i suggest that you get it from whom you know...