19 decembrie 2020

Xiegu G90 External Speaker modification

I like to hack the radios to add new features or to enhance the features already existing.

After playing a while with the G90 I found necessary to have an external speaker because the internal one, altough really loud, it lacks low frequency response.

Trying to connect an external communication speaker gone nowhere because the signal was too weak.

I do have some amplified speakers but I don't want to complicate the setup so, more gain was needed.

Therefore, I opened the Main unit of the radio and start looking inside.


To my surprise, the audio is routed from the LM386 audio power amplifier to the internal speakerphone or to external headphones  with a nice SMD relay. 

When the signal is going to the outside world (a.k.a) Headphones, a 100 Ohm resistor is in series with the HP which explain the low signal. 

I replaced that with 3 10 Ohm in paralell to have some sort of

load in case we shortcircuit the HP Jack. And this is very probable because the signal is going to the tip and to the ring of a stereo 3.5mm Jack. 

This is made to accommodate the usual Stereo Headphones every Chinese ham can buy from Shenzen.

Now the radio has external speaker without too much trouble. 

Because I am using modified Kenwood HS-5 Headphones the audio level is OK.


73 de Adrian yo3hjv @ December 2020

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