Hello everyone
I´m Francisco from Argentina. This is the first time that I post something, so I hope do it in the best way.
I'm trying to make an analogue dj mixer. The main idea it is make fully modular
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I Take the main circuits from an schematic from RANE MP2016. I’ve been working hard but the results are not the best.
The mains problems are:
1-The level potentiometer does not cut the entire signal. When I turn down the volume and close -the potentiometer, It´s keep coming signal, the attenuation achieved is about -62dB, which is quite poor for a an audio mixer. In the schematic I show how I measured with the oscilloscope. I think that is a ground issue or a bad pcb design, but I couldn´t solve it.
2-The LED VU meters introduce noise. I´m using a cheap VU meters that it´s use a KA2284 IC. The noise show´s up when the led s are blinking. The Vcc(+15V ) used by the meters is the same that is used for the audio op amps. I assume that using different Vcc with different regulators It´s going to help, but I appreciate any suggestion.
3-CUE button introduce clicks when it´s pushed off. I´m using a relay to switch on/off the cue, I think the same in the case of vumeters, maybe using different Vcc helps, but I really appreciate any suggestion.
I hope I was clear.
Thank you.