Questions on utilizing optical and rca digital outputs


Also posted at digital section

I am running an Oppo BD 105 as a transport
unfortunately the Oppo only has optical and an rca coaxial digital out


the two dacs I would like to switch between

Audio Research Dac 3 - not as detailed but oh so musical

Conventional 75 ohm coax and  Toslink optical inputs


MHDT Orchid - very detailed and tonally accurate

“BURT”. Digital inouts.   -  75 ohm BNC, usb, rca and.  toslink optical

since the Oppo only outputs optical and an rca digital

would I just be better off swapping out
Digital optical cable between the
Two

or is there an rca optical solution that handles the 75 ohm coaxial connection correctly?
any nice sounding bang for the buck rca  digital cables?

thanks
128x128audiotomb
I'm not sure what you're asking but, first, there is no RCA optical output or cable that I'm aware of. Optical cables on today's devices have either a glass or plastic cable with a Toslink connector or mini-Toslink connector at each end. A digital cable with RCA connectors at each end has a copper wire conductor inside the cable. 
If what you're trying to do is connect the Oppo to both the Audio Research and MHDT DACs you could connect the Toslink output from the Oppo to one of the DACs and the RCA output from the Oppo to the other and on select which output is active from the Oppo.
Impedance (Ohms) doesn't matter in optical connections.  Impedance is for electrical signals, not light.

I do suggest you try a Wyred4Sound Remedy in between though, the ARC DACs really open up when fed a high frequency signal.

Best,

E
I agree with eric's recommendation of the W4S Remedy Reclocker. I have one between the optical output of an iMac and my Pro-Ject DAC and it makes a substantial difference.