AC coupling

I have built an amp that uses an op-amp for its ground circuit

Now i want to build a DAC

I have noticed that the "ground" output of the DAC chip - Vcom is 1/2Vcc

To avoid any short-circuit problems between the DAC Vcom and the amp's ground circuit i want the output of the DAC to be AC coupled

Usually  the output filter is:

>-C-+-->

      R       To Amp

>---+-->

Can i use this instead to decouple the ground circuits as well?

>-C-+->

      R      To Amp

>-C-+->

(BTW the amp is kind of a cmoy)

I want the DC offset of the signal to be 0, especially when the dac is just turned on, and the caps aren't  charged.

With a DC offset=\=0 i will get a spike at the output of the dac.

If i connect the virtual ground of my amp to the usb ground - I will get an initial spike of 2.5V 

Additionally the op-amp on the virtual ground might try and silence the noise on the usb ground wire, or even worse - "fight" against the PC active voltage filters\stabilizers

If i connect the amp's negative rail to the USB ground, the initial spike will be 6.5V

If i connect Vcom to the amp's virtual ground,the initial DC offset of the signal should be 0.

But i suspect that the DAC uses an op-amp to create Vcom, and i don't know what will happen if I connect 2 different op-amps output to output (if they use PNP/NPN at the output i might even get some kind of a diode by connecting them).

My second suggestion totally decouples the DAC from the amp. From the DAC's side it will connect to Vcom and signal-out -> ~0V DC offset even when the amp is just plugged in.

Maybe i should use a transformer instead.

I am worrying about the sr80 (and dt990 when it arrives) connected to the other side of the x6 amp...

I guess it should be fast enough no to cause a big spike at the output

I started worrying because i do hear loud clicks when the DAC in my sony x10 mini is turned on/off (probably to save power)...