Item Tag: McIntosh MAC4280

DISCOUNT OFFERED for LOCAL PICK UP in SAN FRANCISCO Condition: EXCELLENT * one small yellowed POWER LED is out (bottom left) The unit was just tested with FM but I don’t have the other gear to fully test as in phono. IMPOSSIBLE to FIND in SUCH CONDITION in the ORIGINAL BOXES HIGHLY COLLECTIBLE McIntosh MAC 4100 Stereo Receiver (1978-1985) Description 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. Specifications Tuning range: FM, MW Power output: 75 watts per channel into 8 (stereo) Frequency response: 20Hz to 20kHz Total harmonic distortion: 0.05% Damping factor: 30 Input sensitivity: 2mV (MM), 250mV (line) Signal to noise ratio: 80dB (MM), 90dB (line) Output: 250mV (line) Speaker load impedance: 4 to 8 Semiconductors: 31 x IC, 45 x transistors, 62 x diodes, 1 x SCR Dimensions: 473 x 165 x 394mm Weight: 19kg Finish: Satin silver front panel, Solid walnut cabinet

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