SparkFun Forums

[HarrisonHJones]

I'm trying to design a CMoy headphone amplifier with a digital volume control. I want to be able to control the CMoy using a microcontroller so I selected the Maxim DS2890P(since it was in the Eagle Library) and want to use it in place of the variable potentiometer in the following schematic: http://headwize.com/images2/cmoy2_3.gif Does anybody have any suggestions on how to replace the analog pot w/ the digital pot?

[leon_heller]

It just connects in place of the analogue pot, with RH going to the top connection and RL going to the lower connection. The WIPER connection goes where the pot wiper went, to the input. You need to select a suitable MCU and write the One-wire control software for it, of course.

Leon

[HarrisonHJones]

Whilst looking at this schematic(http://headwize.com/images2/cmoy2_5.gif) I noticed that there seems to be a difference between GND and -9v. What is it? I want to replace the 9V battery seen in the schematic with a power input from regulator. How would I? If i did it that way the GND line would be directly connected to the -9V line and that seems to be incorrect.


EDIT: I seems that the GND in that schematic is what's called a "virtual ground" and that the REAL ground from DC Supply would be connected to the -9V