Unlike some of the "deep pockets" around here, I’m sympathetic though I’m not so surprised about the hourly rate as by the time required. An explanation about why the repairs required 14 hours might make the final bill easier to accept. Fourteen hours seems a lot. Inserting (plug-in?) chipsets seems like it should have taken maybe 5 minutes, but that’s 7 hours per amp...so a full day on each. Did you supply the replacement chipsets or did they? AND were they the ones to diagnose bad chipsets as the problem?? Diagnosing would certainly add to the time required. I’m no EE and haven’t a clue how deeply buried inside the amps the chipsets were. Maybe there was a good deal of careful parts removal to get to their location? Afterwards reassembly and warm up followed by some (re-biasing or other "tuning"?) with bench testing on a ’scope?? Maybe even actually playing some music to confirm successful repair! Might help to ask for details about what the job entailed.
PS - not to add fuel to your fire but $1971/14 = $140.79 per hour. Given the quoted $120 per hour, maybe that does include cost of the chipsets.
PS - not to add fuel to your fire but $1971/14 = $140.79 per hour. Given the quoted $120 per hour, maybe that does include cost of the chipsets.