Can anyone suggest a 4 SPST analog switch that would be able to turn on/off that kind of signal?
Also, how would these be controlled by the Arduino? SPI ?
How many Arduino Pins would be involved to control 15 SPST switches? would I have to add a shift register as well?
Try 74HC4066, http://www.nxp.com/documents/data_sheet/74HC_HCT4066.pdf.
So you think that 50 ohm on-resistance is ok? I fear that all those 50 ohms in series will really dampen the output? But I guess the only thing to do is to test it?
If this is really a feasible choice, what if I were to need 30 switches which is the maximum number theoretically possible. I am planning on putting this into an electric guitar with an Arduino Micro, 3 digital pots (6 channels each) and a bluetooth module running from a 9V battery.Will Arduino Micro be able to power all that?
Whether there is too much resistance will depend on how you are wiring the switches and the impedance of the circuit you are using the switches in.
I was looking at those 74HC4066 switches. Actually according to the datasheet, it seems that they do not switch negative voltages?
Could you give more details on how to make a negative power supply, please? But I want to avoid PWM because it causes parasites to be picked up in the circuit - I have that problem already in the current version, so I am going to use digital pots instead...
In my current circuit I use 2 vactrols (LED-LDRs) to make a potentiometer. The LED brightness is controlled by PWM which I have tweaked after lots of experimenting to "phase-correct" PWM at the highest frequency available on my Arduino Micro. I think the grounding is correct. Still sometimes I get a high pitched whistle through the amp. It I turn the PWM "off" by setting the analog out pins appropriately, the whistling stops.