I am trying to connect a microphone to the TT7 kit's audio input. Is there a circuit diagram available for this?
I would like to use either MC1 Miniature Electret Condenser Microphone from Ramsey for input or a simple condenser microphone from Radio Shack 270-092.
I would like to use the amplifier part from the circuit on the bottom this page: http://members.cox.net/rbirac3/Snuffy/tone_detect.htm
using a simple 741 op amp circuit (1458 chip is two 741s) . However, the tone detector chip they use NE567 has a much lower input resistance of 20 K Ohms while the TT7's MC145436 chip has an input resistance of approximately 100 K Ohms. I am worried that the higher resistance will for the TT7's chip will require more amplification but don't want to damage the chip. I am also considering using a Audio amplifier such as this one LM386.
I can't anything on the manual. Thanks!