Hi! I have lurked the forums for a while and searched google thoroughly for the past few weeks, and this is my first post on a
forum (ever), so bear with me. I felt it fell into this category rather than audio, but if a mod could move it if I am wrong then I would appreciate it.
Ok, so my goal is to incorporate an 8x8 crosspoint switch into a guitar. I plan to route a pin to each + and - of each coil (two humbuckers). I have read up that a guitar signal can be less than 100mv up to 1v. I've always heard it was < 0.3v, so I'm going to run a volt meter aside my guitar signal tomorrow to verify my max voltage swing.
I have found a few chips that seem possible for me to use, the MT8809 (http://www.zarlink.com/zarlink/MT8809_DataSheet_Sept11.pdf
), and the MAX456 (http://pdf1.alldatasheet.com/datasheet-pdf/view/73393/MAXIM/MAX456CPL.html
They both seem to have really low capacitance, not much crosstalk, but their voltage swing for the io pins are +/- 0.3v, which could potentially be a problem.
From looking at the datasheet of the mt8809, it seems easier to interface rather than the max456 due to the address table on page 7.
That is only one part of my scheme.
The other, is that the guitar will be phantom powered over a regular 1/4" cable, 2 conductor (mono), meaning the + and - signal for the guitar which is an AC voltage, will also carry 9v DC. (I already have that part done)
My question is, is that if there is 9 volts on that signal, how may I remove that DC voltage from the signal onboard the guitar to not fry the cp switch while still powering my arduino and the other goodies I'm adding to it?
So the cable would carry the signal and 9v, then send only the 9v for the onboard arduino, and only signal to the io pins of the crosspoint switch/pickups.
It almost seems it would be easiest to just have a crosspoint capable of > 9v... *sigh*
I would appreciate it if anyone can give me some insight. I have not bought the chip yet, I'm still searching for the right one.