Only done this once recently, and regretted it! Played at a charity organised by a friend of mine at large city hall. Got there mid afternoon to soundcheck,with my bass rig in the car outside to be used if necessary. There was a Fender bass combo (cant remember which one) on stage available, so played the soundcheck with it and thought it would be okay for the gig later, saving me a long load in! Of course, the gig was a completely different scenario to the soundcheck, levels from all other stuff onstage a lot higher. Plus all the previous bands had obviously encountered the same thing, meaning poor little combo had taken a right hammering all night. We were last on, so by that time the speaker was flapping like mad, ruining for me what should have been a jolly set. So lesson learnt for me...........