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Are you using electret mic as the mic pin is having dc bias voltage? Generally we provide a 1nF? cap across the electret. That filters rf induced on the mic cable. Reg ver 3 drawing 650mA on Rx with volume control at minimum, please check whether the audio amp is landing into oscillation. You could place a 1nF at? Vol mid pin close to the tda2822 and gnd. If the chip is too hot oscillation could be suspected.? Once the Rx? current comes down to expected standard, you can adjust the mos fet currents one? by one after making the gate bias as zero at first stage. Perhaps you might have already exercised all above steps. ? He k once whether the bias regulator output is dropping down not allowing needed Id? for the IRF510s. Hope to see you solving out the issues. Regards? sarma? ?u3zmv On Tue, 7 May 2019, 9:38 pm sdr freak <sdrfreak55@... wrote: I have V3 and i have an idea to rise up the output with an mic amplifier but i want look for an simple homebrew mic amp, but i think the problem is the voltage on mic cable for the amp, i read here in the forum of an simple 2N3906 amp directly after the mic capsuale and without any voltage from battery, only the voltage on the mic line should work, but i have built this and my first usage of it have no output, anything wrong in the circuit i solder or it is the voltage on the mic line that is not enoug.. but i think an mic amp is the first what i need.. |
