This is exactly what I did. The current setup: cd-pro --> DAC --> Pre-amp --> Power amp (is always floating)

This all floating setup works without any drop outs.

I tried the following:

1. I tied the pre-amp to GND. A few drop outs. Not perfectly stable.
   
2. Tied cd-pro to GND and the sound was completely gone. Found the most evil component :-)
   

The I connected a line between DAC GND and cd-pro GND. Now it became almost perfectly stable. I get the best results when the cd-pro is connected to gnd and a line goes from the DAC gnd to cd-pro gnd. No drop outs at all, even thought the wireless router is only 0.5 meter away and they is no shielding or what so ever. Oh yes, the I2C lines are about 20 cm. All not perfect conditions, but it is perfectly stable now!

When connecting both the dac and cd-pro to gnd from the wall socket it becomes unstable without the the line from DAC gnd to cd-pro gnd, although both are connected to the same GND from the socket!!? Therefore I conclude that I need a gnd line next to the cat.5 cable, just like a turntable .

Thanks for all help!

I measured for DC on the line. I measured it at the socket.

Hot to cold --> It varies from -200mV to + 200mV
Hot to GND --> it varies from -40mV to + 40mV.

All audio equipment was switched off during the measurements. Router, Gigabyte switch, squeezebox and modem where not.

One other possible problem I'm thinking of is the line filter used inside the cd-pro. This is a so-called Y-fiter. Y-filters always have a small leaking current to gnd. If I find the time for it I will bypass this filter and see if this is the evil component. ;-)

Normally I do. One socket/electrical output for all audio equipment. But for testing I connected the dac and cd-pro to another wall socket. I know that the grounds of both wall sockets meet each other in the ceiling, so in theory the ground potential should be zero. I`ll try measuring potential difference between them.

What do you want to see? The dac - cdpro?
Atm my dac is just a wooden plank with all modules on it, so there is no star gnd to the chassis and thus not to gnd of the wall socket. I can make a photo of it tomorrow, it`s a bit too late here right now to connect it just for a photo.

Hi Thomas,

I have been busy with some things. I had no time to dig into the teleporter gnd issue. I did however build all modules into the chassis. When I connected my cd-pro again via the sidecar the problem was gone. The dac is still not grounded to the mains ground, so I have still no clue what was wrong. Perhaps it has something to do with all modules now being connected to the metal chassis.

Because it all works fine right now there is no need for posting pictures of my setup.

Thank you all for all help !

Yes, but at first when I tried using the teleporters I had to use an extra gnd line. Just like when using a phono LP player. (between the chassis of my cd-pro and gnd of the dac.


After building it into my chassis I didn't need the extra line anymore.

Must have been "us"

No I don't remember anymore. I borrowed the scope and do not have it at home anymore. Sorry.