SparkFun Forums 

Where electronics enthusiasts find answers.

Questions relating to designing PCBs
By HarrisonHJones
#52053
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?
User avatar
By leon_heller
#52054
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
By HarrisonHJones
#52065
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
long long title how many chars? lets see 123 ok more? yes 60

We have created lots of YouTube videos just so you can achieve [...]

Another post test yes yes yes or no, maybe ni? :-/

The best flat phpBB theme around. Period. Fine craftmanship and [...]

Do you need a super MOD? Well here it is. chew on this

All you need is right here. Content tag, SEO, listing, Pizza and spaghetti [...]

Lasagna on me this time ok? I got plenty of cash

this should be fantastic. but what about links,images, bbcodes etc etc? [...]