Re: Pocket Tutor - hardware update
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Excellent! I hope you enjoy your build as much as I did.
One last thing: I've been using headphones a lot with my Pocket Tutor. If you intend to use headphones too, you will notice that output from the external speaker jack can be overwhelming. (It creates room-filling sound with a 2W speaker.) Will you get to the audio circuit, there are a few options to consider:
a) Use the circuit as is, and keep the volume control near zero. It works, but you can do better.
b) Increase R13 to a larger value (Easy fix, but reduces the range of the on-board speaker); or
c) Add a series resistor between the amplifier circuit and the S-pin (sleeve) of the speaker jack. This is mechanically trickier to do, but will be more satisfying. I suggest a value of around 150-330 ohms. With my headphones, 150 ohms is about right.
d) Make a short adapter cable with a series resistor in it. Easy but clunky.
On Sat, Jul 18, 2020 at 5:28 PM Ken Kaplan <wb2art@...> wrote: