User Manual Q&AAnswer
Feb 15, 2025 - 03:21 AM
The gain of the Technics 101 Audio Amplifier is determined by the value of the feedback resistor (Rf) in the feedback circuit. The resistor can be externally connected to the circuit card connector to achieve the desired gain. The manual provides a table with recommended resistance values for different gain levels. For example, a gain of 35 dB corresponds to a resistor value of 5.6 kohm, while a gain of 50 dB corresponds to a resistor value of 42.2 kohm. Any desired gain between these values can be obtained by calculating the appropriate resistor value using the provided gain equation.
The frequency response of the amplifier can also be tailored by placing a capacitor directly across the signal input terminals of the circuit card connector. This capacitor allows for high-frequency cutoff, and the manual suggests using a .012 MFD capacitor to achieve a -3 dB response at 40 kHz with a 600 ohm source impedance. Any desired frequency response below 1 MHz can be obtained using this method.
It is important to note that the amplifier is resistive in nature, so there is no requirement to match input and output impedance. The amplifier can be terminated with any source resistance from 0 ohms to infinity without affecting its performance, except for noise considerations.
For more detailed information and specific calculations, please refer to the Technics 101 Audio Amplifier Instruction Manual.
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