Hi,
I'm trying to build a 3 channel audio switcher. 3x 3.5mm inputs and 2x 3.5mm outputs one for headpones and one for speakers. I'm using DPDT relays to switch channels. I've added 2 digital potentiometers for volume control, which is controlled by a Pico and Rotary encoder. Because I'm using DC components (DigiPots and Relays), do I need to add blocking capacitors before each of those components?
Another forum mentioned this: "If you use an electrolytic, I recommend a bi-polar type between 10uf and 22uf." (https://modwiggler.com/forum/viewtopic.php?t=171691)
So I was planning on whacking a few 10uf bipolar electrolytic caps in the circuit, but I'm not sure if this is even necessary...
I've attached my current schematic (not including all the digital control circuits, just components directly in the audio path).
Any help would be greatly appreciated! 😀
I'm trying to build a 3 channel audio switcher. 3x 3.5mm inputs and 2x 3.5mm outputs one for headpones and one for speakers. I'm using DPDT relays to switch channels. I've added 2 digital potentiometers for volume control, which is controlled by a Pico and Rotary encoder. Because I'm using DC components (DigiPots and Relays), do I need to add blocking capacitors before each of those components?
Another forum mentioned this: "If you use an electrolytic, I recommend a bi-polar type between 10uf and 22uf." (https://modwiggler.com/forum/viewtopic.php?t=171691)
So I was planning on whacking a few 10uf bipolar electrolytic caps in the circuit, but I'm not sure if this is even necessary...
I've attached my current schematic (not including all the digital control circuits, just components directly in the audio path).
Any help would be greatly appreciated! 😀
Attachments
No, as long as the external circuits do not have any DC when connected.
To be safe, use a series 10uF 35V bipolar at each audio input and output.
To be safe, use a series 10uF 35V bipolar at each audio input and output.
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The whole board is powered by a 12VDC supply which will always be on. The digital potentiometers are powered by 5V from a 7805 voltage regulator, again these will always be on. So I assume DC will always be present in the circuit.
Would the voltage rating of the capacitors matter too much? For example 10uF 35V vs 10uF 50V, is there any drawback to using 50V instead 35V.
So I'd just need them at the input and output of the digital potentiometer?
So I'd just need them at the input and output of the digital potentiometer?
Either DCV would be ok, if bipolar.
The series capacitors would be at each external audio input and output connection.
So connect a capacitor in series just after each audio input jack, and just before each audio output jack.
The series capacitors would be at each external audio input and output connection.
So connect a capacitor in series just after each audio input jack, and just before each audio output jack.