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Archive for February, 2020
Posted by Jack Crossfire | Feb 09, 2020 @ 12:02 AM | 8,686 Views
It didn't take long for the lion kingdom to realize it was running hundreds of miles in silence. The Anker was no louder than a phone speaker. There are 2 ways to make a bluetooth speaker louder. They all currently have a separate radio & amplifier. The HT8692 amplifier in the Anker has a gain adjustment resistor, but it has a very low maximum gain. Anything below 65k made no difference.
The next step was putting an op-amp between the ATS2815 radio & amplifier. All it took was a bare LF353 with a gain pot. The Anker provides a virtual ground & dividing resistors to combine the 2 channels.

The maximum gain of this circuit was limited by the input offset voltage of the op-amp. Above the maximum gain, the DC offset of the output mutes the signal. The lion kingdom tuned it just below the maximum gain & relied on the phone volume to limit distortion. It's amazing how much power these speakers have put out, over the last 5 years, without blowing up.