09-01-2018, 10:50 AM
(09-01-2018, 02:22 AM)Peter08012018 Wrote: 2) I would like to modulate the SG-402 from a plain 3,5 mm audio source. Should this work (given I do have a cable from twice Banana to 3,5 mm mono )
This will work, but I note that the sensitivity of the SG-401 is 1.5V RMS for 40% modulation.
A lot of devices with a 3.5mm output socket produce an output voltage that is considerably quieter than that. And presumably you'll might want more than 40%, so even a full-size CD player might struggle (they should give 2V RMS with a full-modulated disc).
So it is possible that you might need a pre-amplifier to boost the output signal from the source. Such a preamp should be easy to make (a single op-amp would be my choice, but it could be done with a single transistor if you prefer), or would be available as a simple kit. It could also do the stereo-to-mono conversion in a rather more elegant form that the usual "short L and R"
