Direct Optical mode - How to

[innon]

Hi everyone,

i'm a french so excuse me in advance for my english. I have currently 2 phantom Gold.

I started a project related to build a 5.0 configuration for home theater. For this purpose, i bought one center speaker (Dynaudio X28) and 2 rear surround (Monitor Audio Fx bronze).
I connected all these speakers and Phantoms to an A/V receiver (Pioneer LX-701).
As you can notice, my A/V receiver has a pre-out for front. So i plugged my Phantom Gold to these inputs.

More precisely, a RCA cables go to the pre-out towards the RCA input of a A/D converter (Swissonic Converter AD 24/192), then an optical output towards one of my Phantom. With this configuration, i have a 5.0 sound. The issue is that i have sync issue between center and my Phantoms. It's quite audible, specialy for side vocals and musics on movie like an echo.

To avoid this sync issue, i decided to switch my Phantoms to a direct optical mode. However and this is my main issue, when i configure left and right Phantom via direct optical mode and when i split in two the optical signal (with Portta SPDIF Toslink Optischer Digital Audio Splitter) coming from my A/D converter, it just works for one Phantom but not with both. Sound appears without sync issue but just on one Phantom.

Alan said that with an optical splitter, he managed to play both Phantom with left and right. So i don't understand why it doesn't work for me.

Any explanation and advice would be appreciated.

Thanks