Programmable hearing aid

A programmable hearing aid comprising:

• an analog part for processing incoming audio signals arising in plurality of auditory environments, including a first audio signal source, a second audio signal source comprising a telephone coil, pre-amplifier means for pre-amplifying respective signals from said first and second audio signal sources to produce a pre-amplified output, automatic gain control means for automatically amplifying said pre-amplified output with a variable gain dependent on a characteristic of said pre-amplified output to produce an AGC output, filter means for filtering said AGC output to produce a filtered output, a Class D amplifier means having an input supplied with said filtered output and having an output, for amplifying said filtered output with a selected gain, means connected to said Class D amplifier means for setting said selected gain thereof, and an earphone connected to said output of said Class D amplifier means;
• said pre-amplifier means having first and second inputs and first and second amplifier units respectively connected to said first and second inputs, said first input being connected only to said first audio signal source and said second input being connected only to said second audio signal source, said first and second amplifier units each having a settable gain and said first and second amplifier units producing from said first and second audio signal sources, in combination, said pre-amplified output;
• a digital part comprising means for generating and supplying a control signal to said pre-amplifier means for independently setting the respective gains of said first and second amplifier units for selectively amplifying said signals from said first and second audio signal sources individually with respectively different gains or in common with the same gain;
• memory means for storing a stored gain setting for said second amplifier unit for at least one auditory environment using signals from said telephone coil;
• manually actuatable switch means for causing said second amplifier unit to be set at said stored gain setting;
• and
• power supply means connected to said analog part and to said digital part for supplying operating power to said analog part and said digital part.