MCINTOSH-service-manual维修手册vics_bulletins

101IllnfoshMODEL NUMBER MA 230DATE June,1964MODIFICATION MA 230 serial #10c00 to 13C03 to increase overall gain.DESCRIPTION This modification may be incorporated in MA 230units having the above serial numbers to increase theoverall gain.The gain is increased two ways:1.The feedback loop in the phono-tape headinput stages is modified by changing the inputtransistor emitter resistors (R 17 and R 18)from 1.8K 5%watt to 1.2K 5%watt.2.The volume control taper characteristicis changed to allow more amplification at alower setting of the control knob by changing theresistors connected to the rear of the loudnesscontrol (R 39 and R 40)for 47K 10%watt to100K10%老watt.These modifications have been made in all MA 230with serial numbers above 13C03MA230