I must second the correction above. A properly operating MC240 is flat out to about 40 khz at 40 watts and 3 dB down at 100khz with one watt out. When a MC240 has a recapped audio, feedback section and power supply it will sound quite modern. If you are judging the sound of a unit with out of spec old parts this is not the real MC240.
Thanks,
Ron-C