Some amplifiers will then move into our listening room where they are tested with our in-house reference speakers of choice. Our test bench has reference vintage Kef speakers that we're very familiar with which quickly reveal any discrepancies. We've learned over time that some issues are only noticeable to a trained ear while listening to familiar source material. If there are balanced inputs available they will be also be tested.įinal testing involves pushing actual music thorough the amplifier. The amplifier then remains powered on to "burn in" on our test bench for a few hours to make sure there are no heat related issues. If everything reads clean, we will often test for THD (Total Harmonic Distortion) measured by our Keithley distortion meter, and compare it against the original manufacturers specifications. If there is an issue, it will usually be noticeable at this point.
Finally, we run the amplifier to its full rated power into the appropriate resistive load provided by our Sencore amplifier tester. We then power up the unit carefully and run a simple 1k sine wave while monitoring the output on an oscilloscope for signs of distortion or noise. Capacitors are checked for telltale sings of bulging or leaking, resistors are checked for signs of overheating or cracking, and transistors are checked for signs of stress or damage. We start with a visual inspection of all internal components to make sure there are no signs of stress or aging. Our Testing Process for Amplifiers (Solid State) at SkyFi: Height is 9-7/16 inches (23.97cm) including feetĭepth is 14-13/16 inches (37.62cm) including the Front Panel and Knobsĩ4.5 pounds (42.87 kg) net, 108.5 pounds (49.22 kg) in shipping carton Maximum Intermodulation Distortion if instanta- neous peak output per channel does not exceed twice the rated output, for any combination of fre- quencies from 20Hz to 20,000Hz, with all channels operating is 0.005% Maximum Total Harmonic Distortion at any power level from 250 milliwatts to rated power output is 0.005% Minimum sine wave continuous average power output is: 500 watts into 1 ohm load Minimum sine wave continuous average power output is: 500 watts into 4 ohm load Minimum sine wave continuous average power output per channel, all channels operating is:
Built-in Thermal Protection Circuits guard against overheating.Ĭlick here for a PDF copy of the McIntosh MC252 Owner's ManualĬlick here for a PDF copy of the McIntosh MC252 Service Manual
McIntosh Sentry Monitor power output stage protection circuits ensure the MC252 will have a long and trouble free operating life.