From LinnDocs

The Linn DS players do not have surround sound software to decode and playback surround sound streams such as Dolby Digital, DTS etc.

However, you can setup an input on the some Linn Preamplifers, (such as the Klimax Kontrol/new Akurate Kontrol) and Linn DSM/DSI products, to be configured using Konfig to "pass-thro" the stereo audio without the using the Linn Preamplifier/DSI/DSM Volume control.

This allows the Surround processor volume control to control the volume on the front left and right speakers. This ability is called Unity gain

Also make sure that the Delay Mode is set to Direct on this source

The alternative is using Linn DSM products with HDMI connections