[americandreaming]

a while back i started a thread about adding a torx179 to a monicaII dac so that i will have both optical and coax inputs. i would like to use a dpdt to switch between inputs. ideally i would like one pole to switch in the 75 ohm resistor to use the coax and the other pole to bring in the signal from the optical and power it from the board. i finally got all the parts and am ready to put it together but i'm lost!

i know i need to tap +5volts from pin 7 of the cs8414. i think i know which one it is but still am not sure where exactly to solder the wire. this is the picture and the schematic of the dac. i found the 75 ohm resistor on the board and will remove it. after i take it out i should jumper it, correct?

so i have a dpdt switch but i can't visualize what to connect where. i know i want to switch on and off the voltage to the torx and switch a 75 ohm resistor in for the coax and out when the torx is on. how would i wire this? i could use the switch for the output and ground wires of the torx and coax, but this setup would not switch voltage on or off to the torx.

thanks for any help!

 

[rickcr42]

http://focus.ti.com/lit/ug/slau069a/slau069a.pdf

 

[americandreaming]

thanks rick, i went through those pages and checked out the setup.

anyway, i came up with 3 ways to wire this up with a dpdt or rotary switch. which will be the best (i.e. work properly)?

thanks,
larry

 

[rickcr42]

Cool !

good luck man,

rickster

 

[americandreaming]

Quote:

Originally Posted by rickcr42 Cool ! good luck man, rickster

yeah...

so should i flip a coin or what? do they even have 3 sided coins?

 

[Nisbeth]

I'd say option 2/3 looks the most bullet-proof. Just keep wires to/from the switch as short as possible

/U.

 

[rickcr42]

You guys don't wanna know my choices.Not PC

 

[rickcr42]

BTW-in the "too much information" category there is this :

http://www.cirrus.com/en/pubs/proDat.../CS8420_F3.pdf

shoot straight to page 80 for the quick and dirty