MTR Update – Increase audio

 G3CWI pointed out that that can solder a 10uF capacitor between pins 1 and 8 of the LM386 to increase the audio gain by 200%

Lm386 gain

The complete data sheet is here – Page 6 shows that adding the 10uF cap increases the gain from 20 to 200.

The sidetone gets added later in the audio chain, so this mod will not affect sidetone level.

MTR Bottom

One response to “MTR Update – Increase audio”

  1. vk3yy says :

    Hi Allen, I found that the mod increased the level too much on 40m and the limiter is hard limiting on most signals, its also a bit loud in the earphones. Levels are fine on 30m and 20m where there seems to be less gain in the receiver. I plan to reduce the gain a bit with a resistor in series with the capacitor.

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