LM386 Audio Amplifier Circuit. audio listening circuit

Audio Listening Circuit - LM386 Amplifier Circuit
A-15 Audio Amplifier - Law Enforcement Spy Circuit

Wow, 49,000 hits and counting! John Wilsons A-15 Amplifier Is Worth Its Weight in Gold - Better Get His Book Before It Disappears
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audio listening, lm386 audio amplifier circuit
Based on over 3,600 request - For More Than The Schematic On This Circuit
I have written a book on its complete assembly, board layouts and engineering details
- With Much, Much More -
For More Details, Click On The - "MORE INFO" Icon - On The A-15 Book Below
audio listening circuit
The A15 Audio Amplifier Circuit has to be the most reverse engineered unit, by other companies, I think I have ever produced. It was originally produced, manufactured and sold to law Enforcement Agencies back in 1990. I revised it in 1993, 4 transistors, 6 capacitors and 12 resistors removed. I added a 386 audio chip, a See This Circuit In Action In The Video Below. 'OVER 49,000 Hits alone on the YouTube Video Shown Below, and many more are out there! This Circuit is worth its weight in Gold!

The Audio Listening Circuit A15 below was based on a ton of research that I did into STC ( Sound Transmission Class ) and STL ( Sound Transmission Loss ) thru different building materials, doors, windows, concrete, stud walls and how those materials affected frequency loss, suppression and the normal DB levels within a home, an office, a retail store and the audio being intercepted on the backside of the materials above.