I was hoping to use the Cirrus board as a digital effects guitar pedal. I was planning on using line in and line out since the connections make things very simple. However, I have run into some problems with the line out to guitar amplifier connection. First of all, though, I tried recording through line in. When I played what I recorded through my computer speakers it sounded pretty good. When I connected the line out to my guitar amps (Vox AC15C1 / Marshall MG15FX) it had a significant amount of noise coming from the board. I then thought it might be the cord. I tested this by connecting my laptop to my amp with the same cord and playing the same file from my laptop, but this time there was no noise. I checked and the output impedance of the RPi and the Vox are both 15 ohms. One thing I was thinking might be a problem was the max capacitive load for the line out, which was 2 nF, but I haven't been able to find anything about that related to the Vox.
So does anyone know what could be causing noise from the line out only when it is connected to a guitar amplifier? And has anyone tried to use the Cirrus board with the RPi as a guitar pedal?
Thanks
