McIntosh MAC4100

The phono amplifier in the MAC4100 uses a new high technology integrated circuit operational amplifier. Its differential input stage has been optimized for low noise and low distortion performance.

Electronic input selector switching uses field effect analogue switches. The mechanical input selector simply switches small amounts of DC which turn the FET analogue switches off or on. This design eliminates degradation of frequency response and also eliminates noise pickup from long signal paths necessary with conventional mechanical switching. It means, as well, that switch clicks and pops have been eliminated.

The equalizer amplifier is constructed with ion implanted junction field effect operational amplifiers. These new devices amplify signals with a 6 dB better signal to noise ratio than their bipolar counterparts.

Amplifiers are capable of delivering large quantities of power when they are driven to clipping. Clipping is caused when the amplifier is asked to produce more power output than it can deliver with low distortion.

The MAC4100 has a built-in waveform comparator that compares the wave shape of the input signal with the output signal. If the disparity between the two signals exceeds 0.5% a front panel signal illuminates in red at the top of the power output indicators, with any further increase in distortion the Power Guard circuit will operate.